OzGIS INTRODUCTION INSTALLATION DATA ENTRY USER INTERFACE OzGIS FILES GEOGRAPHIC FILES DEVICE FILES MAP TYPES ATTRIBUTE SELECTION QUANTISATION (CLASSIFICATION) GEOGRAPHIC OVERLAYS

DISPLAY CONTROL & MAP DESIGN

MAP REGIONS MAP ANALYSIS DATA PREPARATION BUILDING ZONES & LINES FROM SEGMENTS

SPREADSHEET INTERFACE

MAP PROJECTIONS HARDCOPY MAP PRODUCTION TERRITORY DEFINITION

ADDRESS MATCHING / GEOCODING

SPATIAL OPERATIONS SITE LOCATION / ALLOCATION SITE CATCHMENTS DIGITAL CHART OF THE WORLD MAP DATA FORMATS ATTRIBUTE DATA FORMATS OzGIS GEOGRAPHIC FORMAT FORMAT OF POLYGON GEOGRAPHIC FILES OTHER GEOGRAPHIC FILE FORMATS NAMES FILE FORMAT COMBINE FILE FORMAT DEVICE FILE FORMAT USA CENSUS DATA GLOSSARY OF TERMS

SYSTEM LIMITS

REFERENCES

EXAMPLES









OzGIS INTRODUCTION

Overview

OzGIS is a software system for displaying geographically referenced data as coloured maps on graphics display devices. The maps portray the data values associated with geographic zones by uniform colours, site data by different sized symbols, and line data by different line types.

The system can be used to analyze socio-economic and demographic data produced by censuses and surveys and to support management decisions associated with for example marketing, sales, site and personnel location, and advertising. Other spatial data such as environmental data can be displayed.

The OzGIS web site is www.kisi.com.au

Concepts

OzGIS aims to accept basic data files and to provide most of the facilities required for the analysis and display of attribute data as maps. The analyst has to be able to rapidly use the facilities, so OzGIS provides an interactive user interface. The user interacts via menus and is aided by on-line assistance.

Visual inspection of choropleth maps is the intuitive way to interpret the spatial features of data. An analyst needs to be able to rapidly display and manipulate maps to aid his understanding. OzGIS was designed to enable maps to be changed within seconds so the analyst does not lose his train of thought. OzGIS enables the analyst not just to display a map, but to generate the map that best shows the features of the attribute data. A hardcopy map can be generated as the final operation as a record or for dissemination.

Easy to use systems are either trivial systems, or have a small number of options. The enormous number of options within OzGIS means that it takes some time to understand everything. However, maps can be produced quite simply by using only a small number of options and by using the system defaults.

OzGIS can be considered as one system of a facility for analysis and display of Census type data. The various components are:

Hence you may use: It is expected that an analyst would have access to a PC close to his office. The PC/workstation may be connected via a computer network to provide access to large host machines. The host machines would contain the database systems from which map data could be extracted, and other systems for analysis and hard-copy generation.

Documentation

This manual is supplied on disk and can be viewed by opening it as a file within a web browser.

History

The software was originally developed as part of a research project at the Division of computing Research of the Commonwealth Scientific and Research Organisation (CSIRO) in Canberra for a mapping product called COLOURMAP.

Software development started in 1979 with the purchase of hardware that had been developed for the DIDS mapping system in the White House in Washington DC. This hardware consisted of a PDP11 mini-computer and a DeAnza display system. The display featured a 12bit frame buffer, 4096 value primary look-up table and cascaded 256 value colour table. This enabled maps of up to 4000 zones (e.g. USA Counties) to be displayed and manipulated very rapidly, and is the best hardware so far produced.

The environment changed over several years, with moves to larger PDP11 systems and to VAX and CDC machines. Several display systems were used, Tektronix, Jupiter and RAMTEK, and maps were generated on plotters and film recorders. The system was also available on CSIRONET, an Australia-wide computer network with Control Data and FACOM host computers. The 1981 ABS Census data could be accessed via the SIR/CENSYS system on the Cyber 845. A system was developed to handle the Census district boundaries digitised by the Division of National Mapping, to enable windowing, line simplification and aggregation for production of geographic map data files. The SAS system was available on the FACOM 180 for statistical analysis and display of map data.

The first year of development was supported by Techway, and APASCO supported the development of techniques for retail applications. APASCO used the system and hardware for several years as part of their consulting activities to churn out thousands of maps.

The Division of computing research was split into the CSIRONET computing bureau and the new Division of Information Technology in 1985. Later, CSIRONET was given to private industry. The mapping project was abandoned. The software was resurrected in late 1990 and ported to the IBM PC to produce a system for DOS. A WINDOWS 3.1 version came later. The WIN95 / NT version was released early in 1998. This LINUX version for PCs was released mid 2000.

The purpose of the Guide is to introduce the facilities of OzGIS. The Guide is intended to complement the messages and assistance given during the operation of OzGIS. The user should understand the techniques of statistical data analysis and computer mapping, and also have an elementary understanding of colour representations.

Kingsimons Investments

OzGIS is developed by Kingsimons Investments, a Canberra based software company offering consulting and contract programming services in the areas of: The system was previously developed by an associated company Clever Company which has been absorbed into Kingsimons Investments as a result of the changes to the Australian taxation and company laws in mid 2000.

Map Data Sources

Digital map data can be purchased from many Government and private companies. Demographic data are available from various Census Bureaux.

Free / demonstration data are also available.

Most major suppliers have a site on the Web these days, so use a search engine to look for obvious words such as GIS, map etc. As is usual, once you get to a major site there are lots of links to other places.

Census data

You can start at the US Census bureau site www.census.gov, which has links to other Census bureaux

www.clark.net/pub/lschank/wed/census.html has lots of links to other data

Map data

The USGS is the major site in the USA usgs.gov.au .

AUSLIG is a major site in Australia. It has some free data. www.auslig.gov.au
 
 
 

INSTALLATION

READ.ME

The installation of the OzGIS system is described in the file /usr/doc/osgis???/READ.ME on LINUX and in c:\Program Files\KISI\OzGIS\Documentation for WINDOWS.

Each user has to have some private files.
 

Environment

OzGIS expects whatever is a fairly standard PC. Currently this is:
 

OzGIS initialisation file

The file /home/user/ozhome/OZGIS.INI is the initialisation file for the system on LINUX. Under WINDOWS it is c:\Program Files\OzGIS\OzGIS.ini.

The file should NOT have to be modified initially.

The file should be well commented, and modifications should be fairly obvious.

Ensure that you dont alter the columns used i.e. the file is not free format!

For example, on LINUX:
 

  800 Number of pixels across map display area of window

1 Help level on messages (0=none,2=all)

0 N/A Ring bell when awaiting responses (0=off, 1=on)

0 N/A Automatic redraw of map (0=off, 1=on)

4 Startup debug level (0=none thru 4=everything)

2 Trace level

-family Helvetica font no 1 (default)

-family Helvetica -weight bold font no 2

-family Helvetica -slant italic font no 3

-family Courier font no 4

-family Courier -weight bold font no 5

-family Courier -slant italic font no 6

-family Times font no 7

-family Times -weight bold font no 8

-family Times -slant italic font no 9

-family Symbol marker font

Hardcopy configuration

OzGIS uses the standard WINDOWS printer for output of hardcopy maps.

Windows print drivers are also used for other devices e.g. plotters, special file formats.

WINDOWS Configuration

Use the Sounds icon in the Control panel to enable / disable bleeping when dialog boxes appear.

Typing alt+PrintScreen will load a displayed map into the clipboard from whence it can be used by other packages e.g. inserted into a Word document.
 

DATA ENTRY

Introduction

Most data are entered into OzGIS as external data files. Examples are Census data and Census digitised boundaries. These files come from Census Bureaux, Mapping agencies, data supply companies or your own data-base systems. Some data can be prepared or modified with word processors or spreadsheets.

Several data fornmats are supported. If your format is not supported you have to convert it into one of the supported formats or the OzGIS standard format for the type of file. The data entry options are initiated by choosing IMPORT from the menu.

The main menu enables selection of the type of file:

IMPORT GEOGRAPHIC FILES

IMPORT ATTRIBUTE FILES

IMPORT A NAMES FILE

IMPORT A COMBINE FILE

IMPORT A DEVICE FILE

Choosing a menu item may generate another menu e.g. for GEOGRAPHIC FILES

IMPORT A STANDARD FORMAT GEOGRAPHIC FILE

IMPORT NEW FORMAT SAS GEOGRAPHIC FILE

IMPORT OLD FORMAT SAS GEOGRAPHIC FILE

IMPORT A DLG-3 OPTIONAL FORMAT GEOGRAPHIC FILE

IMPORT A GINA FORMAT GEOGRAPHIC FILE

IMPORT A TIGER FORMAT GEOGRAPHIC FILE

IMPORT A DIME FORMAT GEOGRAPHIC FILE

IMPORT A DXF FORMAT GEOGRAPHIC FILE

.

.

.

.

where DLG-3, TIGER, DXF etc are different data formats.

In all cases, data entry requires giving the name of your data file and supplying the name to be used for the internal file. Data files usually have names that finish with the extension DAT. e.g. LONDON.DAT, A:SALES.DAT.

The one time a full file name can be given within OzGIS is when reading a data file, as it is sometimes inconvenient to rename files . For example you may have TIGER files from the US Census bureau on CD-ROM. Then you could read the files directly by giving the complete file name e.g. E:/18/003/TGR18003.F42

Often data files will need further processing before used for mapping e.g. attribute data may need manipulating by arithmetic expressions or geographic line segments may need thinning and forming into polygons.

Future versions of the OzGIS system may have incompatible internal file formats so always keep important data files.

The system comes with many of the system files already entered e.g. device files. The data files are also provided.

Data entry example

Demonstration Files

The OzGIS system is supplied with a complete set of sample external data files so that the user can become familiar with the system. These files can be inspected to clarify the file formats.

The files are usually in the directory \OZDATA and have names DEM*.*

Example geographic and attribute data

Generally there will be two data files for each map; a file that describes the map boundaries and another for attribute data. The example files are:

Far East Asia

Attribute file - FEA-A

Geographic file- FEA-G

Lowe electorate (Sydney)

Attribute files- LOWE-A1 and LOWE-A2

Geographic files- LOWE-G (zones), LOWE-S1, LOWE-S2 (sites)

These files are already entered (supplied with the system).

Australia

Attribute file - OZ-A

Geographic file- OZ-G

These files have already been input in the demonstration chapter.
 
 
 

Africa in Atlas format

Geographic data files AFRICA.DAT

Hawaii in DLG-3 optional format

These came off a USGS CD-ROM

HAWDLGWB.DAT Water boundaries (islands)

HAWDLGAB.DAT administration boundaries

HAWDLGST.DAT streams

HAWDLGRD.DAT roads

DXF example files from VIC Roads. These have extensions *.DXF

London Cholera

Files are supplied for the classic mapping example where the mapping of the houses where people died during the 1854 outbreak of Cholera onto a street map of inner London, and then mapping the water supply, showed clustering about one pump. The data files are in IDRISI format.

STREET.* London streets (lines)

DEATH.* Where fatalities occurred (points)

PUMP.* Locations of water outlets

ACT / Canberra

Test data are provided for Canberra.

CANBP1.DAT and CANBP2.DAT are shopping centre locations

ACTSHOP.DAT is sample attribute data for shopping centres

L81SEG.DAT are 1981 Census boundaries for the ACT. This file is Crown Copyright of AUSLIG, Australia's national mapping agency. It is supplied with the permission of the General Manager, Australian Surveying and Land Information Group, Dept Arts and Admin. Services, Canberra, ACT.

L81ATTR.DAT is sample attribute data for the above (mangled Census dervived data). L81.ATT is the entered data.

ACTSUBURB.DAT is a points file of names of Canberra suburbs (LGAs).

ACTSUBUR.GEO is the enetered geographic file.

ACTMT.DAT is point data for ACT mountains.

Two files for site catchment examples are:

CATCH.CAT example site catchments and

CANBL81.GEO a geographic file for Canberra city.

D.C.W.

The Digital Chart of the World is an extensive vector database supplied on 4 CD-ROMs at minimal cost.

The test data are from the low resolution browse database from the PO directory

. The files are:

POLINE.LFT

EDG.

POTEXT.TFT

TXT.

Also included is DCWLAND.PRM - World polygons (PO lines data param file modifed to give lines

131, 132 feature code 99 - these close asia at the edges) . This can be used with POLINE.LFT to generate segments that can be used to form polygons.

The DCWWorld.geo file is world polygons (zones).

Example device files

The characteristics of devices and the appearance of maps are given by display files. Data files are provided for all the device files supplied with the system.

The files are already entered on the system and are described in a later chapter.

INTERACTIVE USER INTERFACE TO OzGIS

OzGIS Menus

You choose processing and display options from pulldown menus or from a pop-up menu that appears in the OzGIS window. The menu changes depending on what you are doing.

You will find that some there are lots of menus, and it is difficult at first to know where you are in the menu "tree". To make it more confusing the menus are dynamic e.g. adding something to a map can cause a new menu item to appear that allows you to delete that item.

The general approach is: if the current menu does not have the option you want select from the pulldown menu. You will find that you cannot return to a previous menu at some "main" menus. This prevents loss of map data at various stages; Select "Top menu" from the Control menu.

Main menus appear as pulldown menus.
 

Question Dialog Boxes

Questions are asked by OzGIS when data are required for an operation. The user must supply the data by entering appropriate responses in a dialog box. The format of questions consists of the question, a possible range of values in brackets (if appropriate), a default value in parentheses (if appropriate) and terminated by a question mark. The range of values and default values indicate the form of the expected answer. An example is a request to replace an existing file:

DO YOU WANT TO REPLACE THE FILE [Y,N]?

The user must respond by clicking on YES or NO.

Command Dialog Boxes

Commands are issued by OzGIS when an operation has to be performed by the user. When the operation is completed, control returns to the appropriate menu.

The format for commands consists of a directive, a possible range of values in brackets (if appropriate), a default value in the input field (if appropriate), terminated by a colon. An example is:

TYPE NUMBER OF CLASSES [1-6] (4):

The number of classes must be in the range 1 to 6, and if the user simply presses the "Enter" key a default value of 4 will be selected.
 

Graphic interaction

Graphic interaction in OzGIS involves the use of the mouse to control the cursors on the monitor. Use the left mouse button to select.

The user is directed to operate the mouse etc by the appearance of the cursor on the monitor and by an appropriate command on the screen. The extent of the command depends on the current level of user communication

There are several types of cursors:

Print file

Every program generates printout on a file OZGIS.OUT. This includes: Every time a map is interactively queried the list of map items retrieved is output to a file QUERY.OUT

Error messages are also output to a file WINDOWS.OUT

OzGIS FILE TYPES

File Origins

The following kinds of files must be entered into OzGIS: Data files usually come from Census bureaux, map data suppliers or your corporate database. Data are now available on the net.

External data files must be entered into OzGIS explicitly. This operation permits OzGIS to generate internal representations of the data for efficient processing and to check the data.

Certain files must be prepared explicitly within OzGIS under user direction. These files are:

Some files can be prepared externally or internally. These are: Some files are usually prepared with a word-processor. These are:

File types

The file types will become obvious with use of the system. There are many different types of files used:

File Names

OzGIS distinguishes the various types of files, so you can give the same name to files of different types e.g. you may have a geographic file called AFRICA and also a (probably related) attribute file called AFRICA and you may save the map using these files in a saved display file also called AFRICA.

The system differentiates between files by adding an extension to the given file name e.g. the AFRICA attribute file would actually be AFRICA.ATT

You generally dont have to worry too much about extensions, but they are:

GEOGRAPHIC FILES

Introduction

It is essential to understand the data held in geographic files before the more advanved features of OzGIS can be used.

A geographic file can contain some of:

Topology

For simple mapping of, for example Census data, the fast display polygons are all that are required.

However, OzGIS uses a topological structure for zones and lines which allows manipulation of the geographic data for operations such as:

A complete zones geographic file can be constructed from line segments. See the building process. Such a file contains: Fast display polygons, which are ordered so base polygons are displayed first, followed by islands within them, and so on.
 

DEVICE FILES

Introduction

Device files control the appearance of maps: Experience showed that it is better to have fixed sets of definitions rather than allow the user to specify the display parameters.

There are sets of device files available:

The supplied files have a naming system e.g. The best way to understand device files is to look at the contents, for example:

Select Data-> CHANGE DEVICE FILE

Select C256SV5 .DEV

Select Data-> DISPLAY DEVICE CHARACTERISTICS

You will now get a display that shows the text types (sizes and colours), lines (types and colours) and the various polygon fills as rectangles. Of particular interest are the class colours. The bottom set is a sequence of 121 colours which is designed to give the appearance of increasing attribute values. All the colours will be different (and can be used for "continuous colour" maps). The set of colours above are a 7 x 7 set for bivariate maps. They actually map onto the same set as for single variate maps, so if bivariate maps are to be produced different device files should be used.

Now choose a bivariate device file B256BV2 .DEV and display that.

The bivariate sequence will show a progression of colour in each dimension.

Printers

It is usual to use a black background when displaying maps on the screen as white seems to "wash out" the colours. However, if you want to print maps you will need a white background e.g. device file C256SV1.

Default device file

You should now display a few of the single variate device files (C256SV?) and decide on one that you will use as the default device file.

When you have decided on the default file type exit from OzGIS and:

cd \ozgis

copy C256SV6.DEV DEFAULT.DEV (using the file you have chosen)

This will overwrite the device file that was supplied as the default with the system. Obviously you can select a different device file for display at any time, and you should do so for bivariate maps.

Colour sequences

The colour sequences are designed to provide a colour progression that can help interpret the pregression in values in the attribute data.

The sequences were generated by sampling at equal intervals along curves through uniform colour space, and then transforming the values using a model for the colour response of colour / TV monitors.

OzGIS MAP TYPES

Display Types

There are several types of displays:

Attribute maps

These maps display data from both attribute and geographic files. There are one or two streams of attribute processing for the types of

maps available for zone, line and site attribute data:

The type of map is selected before display and cannot be changed except by returning to the main menu.

Site data can be displayed in several ways:

Line data can be displayed in several ways:

GIS maps

These maps display data from geographics files (without any attribute data. example

Diagrams

Saved-display files

When you have prepared a map and have it displayed you can use the File->Save to store all information

about the map in a file.

File->Open can be used to restore a map display..

Time Lapse Display (not available)

This option was not ported from the PDP11 / DeANZA version but may be partially re-implemented.

Special options are available for the display of time lapse files. The following parameters can be altered:

The zone legend format is not updated during a time lapse sequence, and by default the class description of the legend is set to the "HIGH" and "LOW" format. Histograms and scatter plots cannot be displayed during a time lapse presentation.
 

ATTRIBUTE SELECTION

Introduction

Attribute data is held in attribute files. Each file can have many variables e.g. USA Census data STF1A files can have over 900 variables. This chapter explains the options used to select which attribute is to be displayed on a map.

Various attribute files can be nominated to generate a map display. Attribute may be selected for quantisation and display from attribute files in various ways:

To try these options, display a zones map using attribute file LOWE1 and geographic file LOWE as before and then select CHANGE ATTRIBUTES.

The menu gives the following options:

SELECT FROM A LIST

DISPLAY THE NEXT SEQUENTIAL ATTRIBUTE

SELECT AN ATTRIBUTE FOR DISPLAY BY NUMBER

SELECT AN ATTRIBUTE FOR DISPLAY BY DESCRIPTION
 

Select from a list

A list of available attributes is displayed and one is selected by double clicking with the mouse.

Sequential selection

This option will simply select the next attribute off the file.

By number (position in file)

A particular attribute may be selected by the position within the file. Type zero to generate a list of the attributes on the current file.

By attribute description

The attribute can also be selected by typing part of the description e.g. "FORC" to retrieve "ARMED FORCES". Typing L lists the attributes.

By arithmetic operation

This option enables a new attribute to be generated for display

e.g. the expression " #2 + #4 " forms a new attribute that is the sum of the second and fourth attributes on the input file.

Attributes can also be prepared as a data preparation option and the options are fully described in the relevant chapter.

Zone/Site/Line names

It is your responsibility to ensure that the names referenced by the attributes match the names of the displayed zones, lines or sites in the map. Obviously colours can be assigned only to the zone with names common to the attribute and zone files etc.

Only some of the names have to agree; it is quite common to process attribute data for a larger area than is displayed.

QUANTISATION (CLASSIFICATION)

Introduction

Quantisation is the process of assigning map items to classes according to their attribute values.

The quantisation process is the most important aid for the analyst in understanding the features of the attribute data. The quantisation method and parameters should be chosen logically according to the purpose of analysing the data.

The aim is to display the map that best shows the spatial features and distribution of the data.
 

Attributes are usually presented to OzGIS as values which have to be quantized into a number of classes for display.

A maximum of 10 classes can appear in single variate zone displays and 9 classes (a maximum of 3 per variate) in a bivariate display. A maximum of 4 classes is available for lines and 4 classes for sites.

The best maps usually have a small number of classes; manipulate the map to show the data according to requirements. This contrasts with the production of atlases, where large numbers of colours are used as the purpose to which the map will be put is not known.

To try these options, display a zones map using attribute file LOWE1 and geographic file LOWE as before, and select DEFINE QUANTISATION.

The quantisation menu has the following form:

CHANGE THE QUANTISATION METHOD

CHANGE THE NUMBER OF CLASSES

SELECT THE ZONES FOR QUANTISATION

SELECT THE ATTRIBUTE VALUE RANGE FOR QUANTISATION

You will find that this menu is dynamic as usual. You will find other entries such as SELECT THE LINES FOR QUANTISATION or CHANGE THE NUMBER OF SITE CLASSES for different types of maps.

Try changing the number of classes first and then work through the various methods.

There are other options to change the list of zones to which quantisation is applied and to change the range of values over which the method operates.

Quantisation Methods

Selecting the menu option CHANGE THE QUANTISATION METHOD will display a new menu of the form:

USE EQUAL VALUE INTERVALS

USE QUANTILES

USE SELECTED CLASS INTERVALS

USE SELECTED NUMBER OF ZONES PER CLASS

USE REFINED EQUAL VALUE INTERVALS

USE THE MEAN AND STD DEVIATION METHOD

USE THE NESTED MEANS METHOD

USE THE NATURAL BREAKS METHOD

USE SELECTED PERCENTILES

USE SELECTED CLASS RANGE PERCENTILES

USE INTERACTIVE SELECTION OF CLASS INTERVALS

USE EQUIVALENCE CLASSES

USE CURRENT CLASS RANGES

USE CURRENT NO PER CLASS

USE PSEUDO CONTINUOUS-COLOUR

You should try out these various methods e.g. with the attribute and geographic files OZ.

The following methods for quantization are available for determining the class intervals:

Quantisation Ranges

The range of values over which the quantization is applied can be restricted in all methods. The following options are available for limiting the range: Zones with values outside these limits are assigned the "excluded zone" value and colour, lines and sites are not displayed.

The menu is of the form:

QUANTISE FOR ATTRIBUTE VALUE RANGE

TYPE IN ATTRIBUTE VALUE LIMITS FOR EVERY QUANTISATION

FIX LIMITS AT CURRENT VALUES

QUANTISE FOR AUTOMATICALLY SELECTED VALUE LIMITS

For example a standard legend for percentage data with value ranges 0,25,50,75 and 100 could be generated by choosing extremes to be 0 and 100 and fixing them, and by using 4 equal value classes.

Quantisation Lists

Each of the attribute processing streams has an associated list that holds the names of the items being quantised i.e. zones or lines or sites. There is one list for a single stream, one zones list for bivariate maps, and for two streams there is a list of zones and a list of lines or sites.

Each list selects the items that are to be quantised from the corresponding attribute file. When a map is generated the lists are set to all the names if the attribute files (common names in the case of bivariate maps).

Zone lists can be reset to:

The menu is of the form:

QUANTISE FOR DISPLAYED SITES

QUANTISE FOR ALL SITES IN THE ATTRIBUTE FIL

QUANTISE FOR SITES IN A NAME FILE

EDIT SITES USED FOR QUANTISATION

Zone lists can also be modified by adding or deleting zone names by typing in a name or selecting the zone with the cursor

Site lists and line lists can be modified by giving the names.

Hence the quantisation can take place for a set of items that is independent of the displayed, zone lines and sites (although it is illogical for none to be the same). It is common for the quantisation to be carried out over a larger geographic area than that being displayed.

Sometimes zones are removed because the attribute data are doubtful e.g.

GEOGRAPHIC OVERLAYS (LAYERS)

Geographic files can be displayed on zones, sites and lines maps to add extra information, usually for "navigation" purposes.

Overlays are selected by choosing DEFINE GEOGRAPHIC OVERLAYS off the main map display menu.

A menu appears of the following form:

OVERLAY LINE SEGMENTS FROM A GEOGRAPHIC FILE

OVERLAY MARKERS FOR SITES IN GEOGRAPHIC FILE

OVERLAY NAMES FOR SITES IN GEOGRAPHIC FILE

UNDERLAY POLYGONS FROM GEOGRAPHIC FILE

OVERLAY LINE SEGMENTS FOR FEATURE CODES

OVERLAY MARKERS FOR SITES FOR FEATURE CODES

OVERLAY NAMES FOR SITES FOR FEATURE CODES

UNDERLAY POLYGONS FOR FEATURE CODES

This menu is similar to the one used with geographic (no attributes) maps.

Polygons can be displayed underneath, such as postal districts under a sites map.

Lines are often displayed on top of a map e.g. roads, rivers.

Points can be displayed as symbols e.g. locations of shopping centres.

Point labels can also be displayed e.g. names of towns.

Overlays etc are displayed in the order polygon underlays, then the standard map according to attribute values, then line overlays, then point symbols, and finally names.

Within each type of overlay display takes place in the order the overlays are defined. In some cases order of definition is important as a later overlay can obscure an earlier one.

The basic geographic files contain polygons,lines, points and names. e.g. a file of one level of census boundaries (e.g. blocks) could be displayed as a lines overlay. Files built with BUILD TOPOLOGY also contain approximate centroids of zones with labels being the zone names.

Example.

DISPLAY CONTROL & MAP DESIGN

Introduction

A series of options are available to control the general appearance of maps. These are chosen by selecting CHANGE DISPLAY FEATURES from the main map menu.

The menu is of the form:

DISPLAY TEXT

DEFINE ATTRIBUTE DIAGRAMS ON MAP

ADD STATISTICS TO DIAGRAM

CHANGE ZONES LEGEND

CHANGE LINES LEGEND

CHANGE SITES LEGEND

CHANGE GEOGRAPHIC OVERLAYS (GIS) LEGEND

DISPLAY SYMBOL LEGEND

DISPLAY REGION GRIDS

The actual options that appear depends on the type of map. The options are described in the following sections:
 

Map Quantisation Legends

A legend is always displayed on the monitor when an attribute is quantised for map display. Similar legends are displayed for zones, lines and sites.

The menu to change legends has the form:

REMOVE/INCLUDE CLASS RANGES

ANNOTATE CLASS BOXES WITH 'HIGH' AND 'LOW'

TYPE IN CLASS ANNOTATION (2 LINES PER CLASS)

CHANGE ANNOTATION FOR A CLASS

TYPE IN CLASS ANNOTATION HEADER

REMOVE/INCLUDE CLASS ANNOTATION HEADER

REMOVE/INCLUDE NO. ZONES IN CLASSES

REMOVE/INCLUDE MISSING DATA BOX

REMOVE/INCLUDE EXCLUDED ZONES BOX

REMOVE/INCLUDE UNITS DESCRIPTION

TYPE IN ZONES LEGEND TITLE

REMOVE/INCLUDE ZONES LEGEND TITLE

SPECIFY CLASS RANGE DISPLAY PRECISION

SELECT ZONES LEGEND VIEWPORT WITH THE BOX-CURSORS

The elements of a legend are:

Zone legends have fixed size boxes that give the colours used for the classes.

Site legends have variable sized symbols in a special colour that give the markers and their sizes used for the classes.

Line legends replace the boxes by sample lines in a special colour that give the line types used for the classes.

All text in a legend is written with small fixed size characters.

Display of the legend elements can be controlled by the user. The boxes corresponding to attribute classes are always displayed but the elements (including "excluded zones" and "missing data " boxes) can be removed.

Some of the legend text can be replaced by characters entered by the user on the keyboard, viz.,

The default map layout sets the map image viewport as the left three quarters (approximately) of the monitor, and the legend viewpoints on the right side of the screen. The zone legend is on the bottom, line or site legend above.

New legend viewpoints can be selected with the box cursor. A single variate legend may need more than one column to fit.
 

Overlays (GIS) legends

When line overlays, markers, text at points or polygon underlays are displayed a legend appears that describes the overlays. The text must be specified by the user.

Other Legends

When several line files are being displayed using different lines, or several site files are displayed using different markers, a legend can be added.

The line and marker legends have similar format:

Text

Lines of text can be typed in and displayed on the screen in one of the four available text types. The text is positioned with the cursor. Up to 20 lines of text can be displayed.

Lines of text can be deleted and moved around the screen.

Text is usually added to a map to supply extra information e.g. the name of the geographic region and type of zones, organisation names, disclaimers.

Attribute Diagrams

A menu is available to control diagrams added to an attribute map.

Select DEFINE ATTRIBUTE DIAGRAMS ON MAP.

DISPLAY THE SCATTER DIAGRAM

DISPLAY THE ATTRIBUTE DISTRIBUTION

DISPLAY THE QUANTISATION RESULTS

DISPLAY THE SORTED ATTRIBUTE VALUES

REMOVE/DISPLAY AXES

REMOVE DIAGRAM

CHANGE DISPLAY VIEWPORT

(a) Histograms can be displayed in the map area. The histograms show one of the following:

the number of items (zones or sites) within equal intervals of a single attribute

the number of items within class intervals of a single attribute

the attribute values corresponding to zones sorted in ascending order of attribute value.

The bars of a histogram are coloured according to the class colours in the legend. For two variate displays, two histograms can be displayed one underneath the other. The histograms provide an overview of the statistical distribution of the attribute values.

(b) Scatter plots can be displayed in the map area for bivariate zone displays. The plots show the distribution of zones within the ranges of each attribute. The elements of the plot are coloured according to the class colours in the legend. The scatter plots provide an overview of the statistical distribution of the attribute values.

(c) Statistics can be added to the diagrams:

mean and standard deviation lines

median

A regression polynomial of order 1,2 or 3 can be added to a scatter diagram.

The diagram viewport is selected with the cursor.

Addition of a distribution histogram or scatter diagram (bivariate) add considerably to the information content of a map. They are displayed by default.

Displayed Colours (removed)

Options to change colours are no longer available. They were removed when DOS limits were exceeded. They may be re-implemented.

All colours within a map display can be changed by the user when a 256 colour VGA display system is being used. Individual colours can be selected in three ways:

Any of these ways can be selected by the user.

The set of colours is assigned to map classes and associated map elements by reference to the current device file. This enables colours for all of the classes to be assigned quickly, although individual colours in the set can be modified subsequently. Displayed elements must be identified in order to change their colour.

Certain elements are explictly referenced in the menus associated with colour change, and can be identified by selecting the appropriate menu option. These elements are:

Specific attribute classes, text, markers and lines are identified by number.
 

MAP REGIONS 




Introduction

Map regions enable complex map layouts to be generated. Maps often have only one region, typically zones from one geographic file displayed on the default viewpoint on the monitor. Multiple regions, each with defined window and viewport provide many possibilities:

For example:

These options are for the geographically referenced features of a map. There is a different set of options for defining other features on a map such as text and legends that are simply positioned on the screen.

Definition of map regions is requested by selecting MAP REGIONS from the main map menu after a map has been displayed. A menu then appears of the following form:

CHANGE THE DISPLAYED ITEMS IN THE MAP

CHANGE MAP REGION WINDOW (GEOGRAPHIC AREA)

ZOOM MAP REGION WINDOW ABOUT X-HAIR POINT

CHANGE MAP REGION VIEWPORT (SCREEN AREA)

DEFINE NEW REGION FOR QUANTISED ZONES

DISPLAY MORE QUANTISED ZONES ON A REGION

DELETE QUANTISED ZONES FROM REGION

These few options enable comples layouts to be defined (sometimes with a lot of playing around). If a map is complex it is recommended that the map be saved often so you will not have to start from the beginning if a mistake is made.

Regions

A new map region is established when a geographic file is displayed. The region is defined by the geographic window (or subset) and its displayed area (or viewport) on the monitor.

A standard map consists of one region. The window is the whole of the geographic file and the viewport is most of the screen.

Other regions can be added to a map. A maximum of 10 map regions can be defined in a map. The option DEFINE NEW REGION FOR QUANTISED ZONES enables other geographic files to be added to the map, each on their own part of the screen, and to be coloured according to the attribute file values.

For example, you may want to display a map of 5 counties, where you have 5 geographic files (one for each county) and one attribute file that has the values you want to display. You start by displaying just one geographic file and then use this option to add and position the other four files. You will find that it takes some time to finalise the layout in this type of map.

Regions are identified by number, being the order in which the regions are defined. A standard map has only region number one, and you do not have to specify the region number.

A geographic window is initially the total area of the geographic file (Files are subset as a data preparation process). You can change the part of the geographic file that is displayed by selecting a new geographic extent via the options CHANGE MAP REGION WINDOW (GEOGRAPHIC AREA) or ZOOM MAP REGION WINDOW ABOUT X-HAIR POINT

A new viewport is selected by positioning the cursor on the monitor with the mouse or arrows (i.e. it is a rectangular part of the screen) via the option CHANGE MAP REGION VIEWPORT (SCREEN AREA)

Polygon underlays, line, point and name overlays can be added to any map region. This process is the same as already described in the chapter on overlays except that the region number has to be given if there are more than one.

More than one geographic file can be displayed on a region according to the attribute data with DISPLAY MORE QUANTISED ZONES ON A REGION. For example you may want to display maps of two adjoining states. You start by displaying one of the geographic files for the attribute file in the standard way. You then add the second file to the same region (and adjust the viewport and window). The two states will neatly fit together (if the projection & coordinate system is the same).

Geographic files are automatically windowed, scaled and clipped for display on map regions.

When multiple files are displayed on a region, the precedure order is polygons, quantised zones, lines, sites, line overlays, markers and finally text at points.

Multiple regions can be defined anywhere on the map display area of the monitor. However, if regions overlap the display procedure is established by the order of definition. Therefore the user should consider the order of display carefully in multiple region presentations.

Geographic files can be displayed in any order, and regions can be defined and changed as desired.

Many of these operations destroy the data in the display system memory (the map display is corrupted) so: Select "Display map" from the Control menu.
 

Map List

A list of displayed items (zones, lines and sites) is maintained by the system.

The list can be changed by selecting CHANGE THE DISPLAYED ITEMS IN THE MAP, which displays a menu of the form:

USE THE ITEMS IN A NAMES FILE

USE ITEMS IN THE CURRENT ATTRIBUTE FILE

USE DISPLAYED ITEMS FROM RANGE OF CLASSES

USE THE ITEMS THAT ARE QUANTISED

EDIT THE DISPLAYED MAP ITEMS

The list is sorted into alphabetical order, and the items are displayed using pixels corresponding to the position in the table . This enables items to be selected with the cursor and identified.

A list of flags corresponding to the map list is also held. The flags enable some of the displayed items to be dropped interactively. The flags are usually set to items in the attribute files:

The options are:

Items can be added or deleted by selecting them with the cursor or typing the name.
 

Quantised Zones

Up to 10 sets of zones files can be displayed on defined regions. Adjacent files will automatically join. GKS clips the polygons to the edges of the region viewports. Where regions overlap, the zones of the last one to be displayed will overwrite the displayed data underneath. Zones that are not in the map list are not displayed.

The zones are displayed every time attribute data are quantised for the appropriate classes.

Quantised lines

Up to 10 sets of lines can be displayed on regions. GKS clips lines to region viewports. Lines that are not in the map list are not displayed.

Each file is assigned to a different line, and is displayed in that line colour. Four different lines are available. The results of the quantisation are displayed by using different line types. The attribute data can be quantised into up to four classes, so four line types are used. The line files are assigned to the four available lines according to overall classification when they are defined (e.g. roads, railway tracks and rivers).

Quantised sites

Up to 10 files can be displayed on regions. Sites that are not in the map list or are outside the region window are not displayed. Each file is assigned to a different marker and is displayed in that marker's colour and background colour. Four different markers are available. The results of the quantisation are displayed as different sized markers.

The attribute data can be quantised into up to four classes so four different marker sizes are used. The files are assigned to the four available markers according to overall classification (e.g. owners of banks at the sites).

Line Overlays

The segments from up to 10 geographic files can be displayed as overlays on map regions. Each file is assigned to a region and one of four available lines and is displayed as a solid line in that line's colour. GKS clips the lines to the region's viewport.

Polygon underlays

The polygons from up to 10 geographic files can be displayed as underlays on map regions. Each file is assigned to a region and one of eight available polygon colours.

Marker Overlays

The points from up to 10 geographic files can be used to display markers at points in regions. Each file is assigned to a region and to one of four available markers. Markers are not displayed for points outside the region's window.

Name Overlays

The points from up to 10 geographic files can be used to display names at points in regions. Each site file is assigned to a region and to one of four available types of text. Names are not displayed for points outside the region's window.

Region Modification

The window and viewport of a map region can be modified by selecting a new one with the cursors. Files displayed for quantisation can be deleted from regions, unless the only one of that type.
 

MAP ANALYSIS 




Introduction

Selecting ANALYSE from the main map menu enables further analysis of a displayed map (with attribute data). The following menu appears:

INTERROGATE MAP DATA

GENERATE MAP REPORT ON FILE OZGIS.OUT

DISPLAY ATTRIBUTE STATISTICS
 

Map Reports

An option is available to write a full map report (giving details of the displayed items, their attribute values and class numbers) on the file OZGIS.OUT
 

Attribute Data Statistics

The statistics of displayed attributes can be computed and displayed under user control.

The following statistics are computed for a simple attribute:

For pairs of attributes (bi-variate displays) the above statistics are computed for each attribute, as well as

Map Interrogation

When a map has been displayed, it is possible to interrogate the map data interactively. The actual menu depends on the type of map, but is of the form:

LIST DATA FOR A CLASS RANGE

LIST DATA FOR NAMES TYPED AT TERMINAL

LIST DATA FOR ITEMS IN A NAMES FILE

LIST DISPLAYED SITES

LIST QUANTISATION SITES

LIST SITES WITHIN WINDOW SELECTED WITH BOX-CURSOR

LIST SITES WITHIN DIGITISED POLYGON

LIST SITES WITHIN CIRCLE, TYPED IN RADIUS

LIST SITES WITHIN CIRCLE, CURSOR SELECTED RADIUS

The details generated by interrogation are the names of the zones, lines or sites, the values of the displayed attributes (one value for single variate displays, and two for bivariate) and their assigned class number.

The map can also be interrogated for the textual information held in text attribute files. This enables non-numeric information to be accessed in the same way as the values in standard attribute files.

The options for interrogation are:

(a) class number range - items (zones, lines or sites) within a specified range of class numbers.

(b) single item identification - zone line or site selected by entering its name at the keyboard.

(c) set identification - items selected by a names file, items in map, or items in quantisation lists.

(d) Lists - The names of all the displayed items are held in one list. Each attribute stream has an associated list of items that are being quantised.

(e) Interactive selection

The list of items selected interactively is also output to a file QUERY.OUT for use either as a names file or for export to other systems.

DATA PREPARATION

Introduction

The raw data are input to the system using IMPORT DATA FILES. However, the data often need further processing. Also, some data needed within the system cannot be specified as data files and need to be prepared. These facilities are provided by the PREPARE option in the top menu.

The main menu is of the form:

PROCESS ATTRIBUTE FILES

PROCESS GEOGRAPHIC FILES

PROCESS NAMES FILES

OUTPUT EXTERNAL DATA FILES
 

Attribute Files

The PROCESS ATTRIBUTE FILES menu is:

FORM ATTRIBUTES WITH ARITHMETIC EXPRESSIONS

AMALGAMATE ATTRIBUTE DATA FOR AN COMBINE FILE

A new attribute file can be generated from an attribute file and a combine file by selecting AMALGAMATE ATTRIBUTE DATA FOR AN COMBINE FILE. The combine file defines new zones (or site catchments) in terms of the names referenced by the attribute file.

For example, you may define sales territories in terms of postal districts and put the definition in a combine file (manually or via territory definition). You would then amalgamate both the geographic file of postal district boundaries and any attribute files based on postal boundaries to produce files for mapping.

Attributes can also be derived from existing attributes by applying arithmetic operations to the attribute values via FORM ATTRIBUTES WITH ARITHMETIC EXPRESSIONS

A common application is preprocessing Census data before display to form the desired attributes.

Attributes are identified by the character # followed by a number, indicating the sequential position of the attribute on the input file e.g. #10 represents the tenth attribute). An example of an expression to form a composite attribute is:

(#1+#2)/2 > 0 < 1000

This creates a new attribute whose values are half the sum of the values from the first and second attributes on the input file. Any valid arithmetic expression is acceptable. The output values are limited to the given range.

Functions available are:-

Functions removed from the PC version are: Pi is referred to as PI.

Operators are:

Expressions are evaluated left to right and have a limit of 70 characters. Parentheses should be used to ensure there are no ambiguities.

The user must give a 30 character attribute description and 10 character units description for each new attribute that is generated.
 

Geographic Files

The menu is of the following form:

SUBSET FOR ZONES LIST

SUBSET FOR LINES LIST

SUBSET FOR SITES LIST

AMALGAMATE ZONES FOR A COMBINE FILE

JOIN LINE SEGMENTS FOR POLYGONS

SIMPLIFY (THIN) LINE SEGMENTS

EXTRACT BOUNDARY SEGMENTS

Often the geographic region covered by a geographic file will be much larger than is required. Geographic files can be subset (windowed) on the basis of a list of required display items (zones, sites, lines).

Line segments can be simplified to reduce the number of points that have to be processed. This is used to speed up display where the resolution of the digitised data are higher that that needed for display terminals.

Line segments that form polygons can be joined together into long segments. Where many short segments are used this process, in conjunction with simplification, can sustantially reduce the disk storage required and speed processing.

The zones in a geographic file can be amalgamated according to a combine file to generate a new geographic file. The new file contains the new zones. The same combine file can be used to generate attribute data for the same new zones. For example, you may amalgamate basic Census zones into zones at a higher level or into sales territories.

Often digitised data are only available in polygon form for primitive mapping systems. Polygons are all that are required for basic choropleth mapping, but successful amalgamation of zones into higher level zones (e.g. for territory definition) requires the boundary segments. Usually the boundary segments will have been digitised and used to form the polygons. A facility is available to reverse the process. When Census data are processed, only the lowest level of Census district need to be purchased along with the lists of base districts that form higher level zones. Once the boundary segments have been obtained they can be amalgamated into the higher level zones.
 

Names Files

Names files give lists of items (zones, sites,lines) that are to be processed. These lists can be generated from other types of files. These options are particularly useful when the names files are to be modified.

The menu is of the form:

SAVE ATTRIBUTE FILE NAMES AS A NAMES FILE

SAVE GEOGRAPHIC FILE ZONES AS A NAMES FILE

SAVE GEOGRAPHIC FILE LINES AS A NAMES FILE

SAVE GEOGRAPHIC FILE SITES AS A NAMES FILE

EDIT A NAMES FILE

For example, you may output the names from a Census attribute file to a names file, edit it with a word processor and the use it to subset a census boundary (geographic) file to produce the desired map region.
 

Output to Data Files

Options are provided to output internal files as data files so they can be modified with word-processors for further processing. The menu is of the following form:

GENERATE ATTRIBUTE TEMPLATE DATA FILE

OUTPUT NAMES DATA FILE

OUTPUT ATTRIBUTE FILE IN SIMPLE (SAS) FORMAT

OUTPUT COMBINE DATA FILE

Names files can be edited to change the lists of items used for processing.

Attribute files can be output in simple database format.

Combine files can be modified as part of the definition of territories and sites.

Attribute templates can be generated for preparation of attribute data with a word-processor. This is also useful for displaying new boundary data when you have no attribute file. The file can be input as a database format attribute file.

BUILDING ZONES & LINES FROM SEGMENTS

Introduction

Geographic data, such as Census boundaries, are often supplied as lines which have to be connected to form polygons or complex lines.

Zone boundary data can be supplied either as the complete set of points for the outsides of each polygon or as the line segments that make up the boundaries.

Most segments will be common to two polygons so only about half the number of points are required. The segment form also allows zones to amalgamated into larger zones (by dropping internal segments) and to be thinned (by dropping excess points).

The segments form of data is preferred to polygon formats.

The build process takes line segments and joins the ends together to form polygons. The names of the zones on each side of the segments are used to derive the zone names.

Complex polygons are handled. Zones can be made up of many polygons, both disjoint polygons and polygons within polygons. The display order of the polygons are calculated so e.g islands within lakes within zones all appear.

Line segments can also be built into complex lines to which attribute data can be assigned.

It is usual to line simplify (thin) the segments before building as many digitised boundary files (e.g. census) are at a much higher resolution than require for the display. Joining of line segments and further thinning may follow.

If the message"TOO MANY POINTS IN POLYGON" appears you will have to line simplify your data. The building process can use a lot of disk space, effectively the product of the max number of polygons in a zone and the number of zones. Options are provided to help control this.

When the line segments were generated from spatial operations, arithmetic roundoff can produce slightly different endpoints. A tolerance factor can be given to help join faulty points. The tolerance is usually zero.

Faulty Digitised Data

The algorithm assumes that the segments have been produced on a proper digitising system and are correct e.g. it is assumed that end-points meet and the segments do not cross. Problems such as repeated segments, missing segments etc may cause problems. Ensure you use the program with trace turned on. If necessary turn on debug and look at the OZGIS.OUT file.

Use the file interrogation option to find the statistics on the geographic file

e.g. the number of zones.

The top menu option PREPARE DATA FOR DISPLAY can be used to generate a prototype attribute file (simple format) from the zones in the geographics file and hence get some test data that can be entered via IMPORT DATA FILES to form an attribute file. Displaying both files via SIMPLE CENSUS-TYPE MAPPING will allow the file to be checked.

Building example.

SPREADSHEET INTERFACE

Introduction

The OzGIS system was designed to provide advanced mapping capablilities that could be interfaced to other systems such as: The main software systems that are of value are spreadsheets and database systems for handling attribute and other data. These software systems (e.g. Lotus, Excel, MS access, Paradox) are easy to use and are growing in sophistication.

The OzGIS system interfaces to these systems via the Lotus WK1 file format.

Data must be held in a tabular format where the first column is ALWAYS the primary key and is the same as the map identifiers (and usually alphanumeric)

Other columns depend on the type of data.

WK1 format data can be imported into OzGIS via menu options in the data entry process and exported via options in the data preparation module.

Attribute data

Data from spreadsheets can be both imported and exported in WK1 format.

The spreadsheet must be set up in a fixed format:

e.g. the file DEMO123.dat can be read into the spreadsheet. It should look like:

 
POPULATION GROWTH SALES
NUMBER $
ABBOTSFORD 7418 237
BURWOOD E 9925 955
CONCORD 8984 202
CROYDON N 9369 298
CROYDON W 735
FIVE DOCK 9903 716
HABERFIELD 727
HOMEBUSH 6631 704
HUDSONPARK 4668 71
MORTLAKE 1725 198
STRATHFIELD 6285 663
YARALLA 9875 516

For example, with Microsoft Excel for Windows, the test file can be read by choosing the option "Open" from the "File" menu and giving the test file as \OZDATA\DEMO123.WK1. A spreadsheet in the above format can be output by selecting the "Save As" option from the "Files" menu and using the WK1 format option.

Names Files (lists of names)

The first column of the spreadsheet can be output as a WK1 file and then imported into OzGIS as a names file to control the processing.

A names file can be exported as a single column WK1 file and hence used to initialise a spreadsheet.

Names can also be output from a geographic file, where the list is one of the zone names, line names or site names.

Points

Site names and their (X,Y) locations can be exported as WK1 files.

Points output from a spreadsheet can be input as a points geographic file. The columns must have names called exactly "X" and "Y". You can also assign positive numeric feature codes by a column called exactly "Feature Code". If the column is used, a feature code must exist for every point (use zero if not required).

Territories and Catchments

A combine file containing the definitions of either territories or site catchments can be exported from OzGISas a WK1 file. The column names are "Territory" and "Weight" (the first column is the zone name).

Addresses

You can export a column called "Address" as a WK1 file from a spreadsheet and import it into OzGIS for reformatting as a data file that can be used for geocoding.

MAP PROJECTIONS 




Introduction

The projection options will process a geographic file to form a new geographic file converting either from (Longitude,Latitude) to a projection or in the reverse direction.

Often projections will not be of concern, as map data will be used as supplied. However, if data comes from several sources in different projections, the files may have to be converted to a common coordinate system. You will have to have a basic knowledge of the projection you want to use

e.g. that AMG is UTM with the Australian Spheroid and a false origin

(500000,10000000).

The options are based on public domain software from USGS.

Projections processing is initiated by selecting MAP PROJECTIONS from the top menu

The main menu is:

CHOOSE FROM PROJECTION SET 1

CHOOSE FROM PROJECTION SET 2

CHOOSE FROM SPHEROID SET 1

CHOOSE FROM SPHEROID SET 2

DEFINE NON-STANDARD UNIT

WRITE PROJECTION DEFINITION INTO GEOGRAPHIC FILE

TRANSFORM LAT / LONG FILE TO PROJECTION

TRANSFORM PROJECTION FILE TO LAT / LONG

DISPLAY PROJECTION PARAMETERS FOR GEOGRAPHIC FILE
 

Precision

Vertices are stored in single precision in OzGIS (there is not enough memory on the PC to do anything else). This means an accuracy of seven digits, so some values may not be accurate e.g. UTM may be a few metres out.

Latitude / longitude

Latitude / longitude data must be given with units degrees.

Latitudes are negative in the Southern hemisphere.

Usual value ranges are:

Longitude -180 to +180

Latitude -90 to +90

Note that the X value in data files is the longitude.

examples: (-100.0,50.0) i.e. longitude -100, latitude 50

(145.0, -42.0) a point in Tasmania

Projections

Several projections are supported:

Ellipsoids

Several spheroids are available. The default is either Clarke 1866 or the 6370997 metre sphere where a radius is asked for.

Using projections

The parameters of the projection are stored in the geographic file. When the data are first entered the projection is usually set to 'undefined', unless it is known e.g. Census boundary data are usually set to geographic (lat/long units degrees) by the data entry process.

The first operation is often to define the projection of a new geographic file and store the parameters in the file header. Hence you have to choose the projection, spheroid if non standard, and then the option WRITE PROJECTION DEFINITION INTO GEOGRAPHIC FILE.

Transformation is to and from lat/long. Hence conversion from one projection to another has to take place in two steps.

Example
 

HARDCOPY MAP PRODUCTION

Printers

Selecting File->Print will enable the displayed map to be output to your printer.

You will probably need to use the printer setup option first and use landscape.

You will usually use a device file that has a white background if you are printing on white paper.

Clipboard

The standard WINDOWS facility of Alt+Print screen can be used to load the current map into the clipboard. From there it can be imported into other packages e.g. into a Word document.
 

Photographs

Colour slides can be successfully produced by photographing the screen.

The room has to be dark and any lights on the PC covered. Watch for reflections around the edge of the screen (blacken around the screen).

You will have to experiment. Initially bracket exposures.

Lenses with long focal lengths reduce the curvature of the screen.

An initial setting is:

250mm lens

200 ISO film

f/8 at 1 second

TERRITORY DEFINITION

Territories can be defined in terms of zones (polygons) in some displayed base map.

Usually territories are to be developed from base zones according to some criterion; e.g. Sales territories should all have similar sales potential; e.g. School districts should have similar numbers of children.

The operations are as follows.

First choose the New pulldown menu:

START NEW SET OF TERRITORIES INTERACTIVELY

START NEW SET OF TERRITORIES FROM COMBINE FILE

This gives the choice of starting a new set of territories by selecting regions with the box-cursor, or reading in a pre-defined set of territories off a combine file that is probably the result of a previous run of OzTerr.

The Define menu is used to specify the zones in each territory

DISPLAY TERRITORY NAMES

DEFINE NEW TERRITORY

DELETE A TERRITORY

ADD ZONES SELECTED WITH BOX-CURSOR TO A TERRITORY

ADD A ZONE SELECTED WITH CURSOR TO A TERRITORY

DELETE ZONES SELECTED WITH BOX-CURSOR FROM A TERRITORY

DELETE A ZONE SELECTED WITH CURSOR FROM A TERRITORY

CHANGE BASE ZONE ATTRIBUTES

CHANGE THE QUANTISATION METHOD

OVERLAY MARKERS FOR SITES IN GEOGRAPHIC FILE

OVERLAY NAMES FOR SITES IN GEOGRAPHIC FILE

OVERLAY LINE SEGMENTS FROM A GEOGRAPHIC FILE

OUTPUT TERRITORY NAMES AS GEOGRAPHIC FILE

OUTPUT TERRITORIES AS COMBINE FILE

You define territories using the options:

DISPLAY TERRITORY NAMES

DEFINE NEW TERRITORY

DELETE A TERRITORY

Usually you are trying to balance territories e.g. you may display an attribute that is number of customers and the try to give each salesman a territory with about the same number of customers. To do this you define the correct number of territories making a guess at their size and then shuffle the zones between the territories while monitoring the results by using "Display Map" to display the map. The options relevant to modifying territories are:

ADD ZONES SELECTED WITH BOX-CURSOR TO A TERRITORY

ADD A ZONE SELECTED WITH CURSOR TO A TERRITORY

DELETE ZONES SELECTED WITH BOX-CURSOR FROM A TERRITORY

DELETE A ZONE SELECTED WITH CURSOR FROM A TERRITORY

You can add overlays to the displayed map to provide "navigation" with:

OVERLAY MARKERS FOR SITES IN GEOGRAPHIC FILE

OVERLAY NAMES FOR SITES IN GEOGRAPHIC FILE

OVERLAY LINE SEGMENTS FROM A GEOGRAPHIC FILE

Finally the territory definitions can be output to a combine file that can be used to amalgamate the base zones and related attributes (see data preparation) to get a geographic and attribute file for mapping by using the option OUTPUT TERRITORIES AS COMBINE FILE.

You should have line segments data for amalgamation. If you started with polygon data, the polygons will simply be renamed during the amalgamation process.

You can also output a points geographic file that can be used as an overlay to label the territories on a map by using OUTPUT TERRITORY NAMES AS GEOGRAPHIC FILE.
 

ADDRESS MATCHING / GEOCODING

Introduction

Many organisations have data which are spatially referenced by addresses, such as customer databases. These data can be shown on a zones map by accumulating the data within each postal district and displaying the results using digitised postal district boundaries. Examples are total number of customers and average sales amount.

Digital data are now becoming available that contain address information e.g. the US Census TIGER data. These data enable the locations of the attribute data to be extracted as points and maps produced with or without related attribute data.

The OzGIS system allows digitised road data and their associated addresses to be processed. Sets of addresses can be processed to produce geographic files of point locations. These point files can then be displayed in the usual ways, either as symbols or names as map overlays or as sites sized according to some attribute data.

For example, a bank may want to extract points using the addresses of some customers and then map the average monthly account balances.

Addresses

An address is made up of three parts, a number, a name and a postal code. Examples are:

123 Main Street 654321

Hyde Park

12 Funny Farm Drive, Hicksville 2601

1. The number is a simple integer. Common variations such as 22A, 5-6, 5/66 etc are not supported. If a number is not given the point will be placed in the centre of the geographic feature.

2. The name must be given, and is the main part of the address for matching.

3. The postal district is an integer number that helps processing in cases where the same address name is used in different districts. It need not be given.
 

Data entry

Lines data can be entered with the normal process. Addresses are supported for TIGER data and data in standard form. Other formats will be supported according to availability of data and demand.

Only line data is supported as that is what is currently available. Typically the data will be roads.

Two ranges of street numbers will usually be associated with a road, a set of odd numbers down one side and even numbers down the other e.g. a digitised line segment may have road name "Hollywood Boulevarde" and number ranges 111 to 179 and 120 to 220.

A road may also have one range (e.g. 1 to 200) or no range may be given. The order of the road numbers defines the direction of the road. The direction does not have to be the same for the odd and even numbers. If two ranges are given and one is not odd and the other even, a single range is derived from the limits, but the direction must be the same as defined by the two ranges.
 

Address Matching

An option is provided in the data preparation process to match addresses in a data file with those in the digitised line data in a geographic file. The major difficulty is the matching of the road names allowing for differences in spelling.

After a match is found, the number in the given address is used to find the distance along the road (using the ranges) and hence a location is calculated.

The set of addresses are given on a data file that has the following:

1. An identifier that can be used to attach attribute data to the point and which can be used as a label on maps. If no identifier is given the road name will be used. This identifier would often be a database primary key.

2. The road number. If not given the generated point will be the centre of the road.

3. The road name. Mandatory.

4. The post (zip) code. Optional.

A geographic file of points is generated. Any addresses that cannot be matched are listed on the OZGIS.OUT file.

Matching Process

Matching takes place on upper case characters i.e. case is not significant e.g. "Main St" and MAIN st" match.

Multiple blanks are removed e.g. "Grand Parade" matches "Grand Parade".

A parameter file is used to convert parts of the names. This is commonly used to handle abbreviations e.g. ROAD and RD.

Matching is controlled by a level:

Level 1. Every character in the names in the geographic and data files must be the same e.g. "PHREDS ROAD" and PHRED ROAD" are not the same.

Level 2. Every character of the shorter name must match the other e.g. "phred" would match the above two strings.

Level 3. The first word in each name must match e.g. "Bloggs Street" and "Bloggs Ave" match.

Level 4. Matching is carried out by using derived names e.g. vowels are all treated the same, repeated letters are removed, non alphabetic characters are all the same.

Level 5. Matching uses the "soundex" algorithm
 

Procedure

Address matching is an option in the data preparation process. Select PREPARE DATA FOR DISPLAY from the top menu, which gives the menu:

TUTORIALS & SYSTEM INFORMATION

PROCESS GEOGRAPHIC FILES

PROCESS ATTRIBUTES FILES

PROCESS NAMES FILES

OUTPUT EXTERNAL DATA FILES

ADDRESS MATCHING

CHANGE DEVICE FILE

So you choose ADDRESS MATCHING, which displays the menu:

EXACT MATCHING FOR POINTS OVERLAYS

MATCH FOR START OF ADDRESS FOR POINTS OVERLAYS

MATCH FOR FIRST WORD OF ADDRESS FOR POINTS OVERLAYS

DESPERATION MATCHING FOR POINTS OVERLAYS

EXACT MATCHING FOR SITE MAPPING

MATCH FOR START OF ADDRESS FOR SITES MAPPING

MATCH FOR FIRST WORD OF ADDRESS FOR SITES MAPPING

DESPERATION MATCHING FOR SITES MAPPING

These options correspond to the 4 matching levels for either point overlays or site mapping.

You have to specify a number of files:

1. the geographic file that contains the roads and the road names and address limits

2. Your data file containing the addresses to be matched

3. A parameter file of abbreviations to help the matching process e.g. AVE is defined as the abbreviation for Avenue

4. the name of the geographic file to be generated with the points location After you have generated the points geographic file you should check the file OZGIS.OUT to see how well the addresses were matched. You may then want to change some of the addresses in the data file to improve the hit rate.

You can now map the data with the OzGIS program. This is covered in other chapters, but briefly:

DISPLAY GEOGRAPHIC FILES (NO ATTRIBUTES) is used to display the points as symbols.

You would probably then use DEFINE GEOGRAPHIC OVERLAYS and add your roads file as a lines overlay and also overlay the names of the points.

DISPLAY SITES FOR AN ATTRIBUTE FILE would be used if you have attribute data for the points. You would probably add the roads as a lines overlay and the identifiers as a names overlay.

DISPLAY ZONES AND SITES FOR TWO ATTRIBUTE FILES could also be used if you want to display other data such as Census data as a zones map underneath the points with their attribute data.

The points could of course be added as overlays to any map.

Data

You specify the addresses you want to match in a data files with fixed format records:

10 bytes Identifier. If blank the road name is used (first 10 bytes)

50 bytes Address

For example, the demonstration file DEMOMTCH.DAT looks like:

EXAMPLE ADDRESSES FOR MATCHING - DEMOMTCH.DAT

ADDRESS001 1 GReat north road 2600

666 GReat north road 2600

JOE BLOGGS 333 GReat north road 2600

ADDRESS004 GReat north road 2600

333 GReat north road

PIZZA KING GReat north road

ADDRESS007 333 GReat 2600

HARRY S 333 GReat north rd 2600

ADDRESS009 333 GReet narth read 2600

ADDRESS011 666 GReat north road 2600

ADDRESS012 666 Molonglo Gorge 2600

ADDRESS013 Molonglo Gorge

11 Northbourne Ave 2602

ADDRESS015 44 Northbourne Ave 2600

ADDRESS016 10 Northbourne Ave 2600

ADDRESS017 68 Northbourne Ave 2600

ADDRESS018 57 Northbourne Ave 2600

ADDRESS01940 EPPING HWY

ADDRESS020 33 EPPING HWY
 

Abbreviations parameter file

A parameter file must be given to allow for abbreviations such as ST, AVE, RD

A sample file from the USA Census TIGER documentaion is provided \OZGIS\USA.PRM

You should set up your own abbreviation file. The shorter it is, the faster will be the matching process.

The first record of the file is a comment, and each following record is:

30 bytes text

10 bytes abbreviation

The file must be in upper case, and the abbreviation must be shorter than the text string.

The demonstration file is DEMOMTCH.PRM:

Address matching parameter file DEMOMTCH.PRM

AVENUE AVE

BOULEVARD BLVD

CIRCLE CIR

DRIVE DR

FREEWAY FWY

HIGHWAY HWY

MOTORWAY MTWY

PARKWAY PKY

PLACE PL

ROAD RD

STREET ST
 

Handling Errors

The results of the matching process are written to the log file OZGIS.OUT Each data record is listed with either "MATCHED", "DUPLICATE" or "REJECTED". When the names match both the data and geographic file addresses are listed as well as the level of the match. The output will be of the form:

======= ADDRESS MATCHING AT LEVEL 4 ======

GEOGRAPHIC FILE demoaddr

ADDRESSES FILE demomtch

PARAMETER FILE demomtch

MATCHED 333 GReat north road 2600

MATCHED 666 GReat north road 2600

NO MATCH 666 Molonglo Gorge 2600

NO MATCH 68 Northbourne Ave 2600

MATCHED 11 EPPING HWY 0

MATCHED 33 EPPING HWY 0

NO MATCH 33 EPXXING HWY 0

SPATIAL OPERATIONS

Introduction

New geographic files can be generated as the result of spatial operations such as union and intersection between the spatial objects in two input geographic files.

The options have not been fully tested.
 

Operations

The operations take place between the objects in two input geographic files, with the resultant objects being output to a new geographic file. The following operations are supported: Two levels of polygons will be supported:

1. Simple polygons Single polygons are processed. There is no regard for polygons inside other polygons. Polygons with the names OUTSIDE or INSIDE are ignored. This will often be all that is required. These data can have been entered into the system as one of the polygonal formats supported (SAS, Atlas etc).

2. Complex polygons NOT IMPLEMENTED YET This handles zones which are made up of any mixture of polygons, some of which can be inside others to a considerable depth. The results of the polygon processing is a file of line segments that can be built into polygons with the zone/polygon building process.

Feature codes

Processing can take place for a range of feature codes or the whole of the files can be processed. A new feature code must be specified for the generated objects. Optionally the existing feature codes for both files of objects can be added as well.

Procedure

When the SPATIAL OPERATIONS item is selected from the top menu the following menu appears:

INTERSECT POINTS (SECONDARY) WITH SIMPLE POLYGONS (PRIMARY)

INTERSECT LINES (SECONDARY) WITH SIMPLE POLYGONS (PRIMARY)

INTERSECT SIMPLE POLYGONS WITH SIMPLE POLYGONS

UNION OF SIMPLE POLYGONS WITH SIMPLE POLYGONS

INTERSECT POINTS WITH SIMPLE POLYGONS FOR FEATURE CODES

INTERSECT LINES WITH SIMPLE POLYGONS FOR FEATURE CODES

INTERSECT POLYGONS WITH SIMPLE POLYGONS FOR FEATURE CODES

UNION OF POLYGONS WITH SIMPLE POLYGONS FOR FEATURE CODES

You select the appropriate option. You can either process all the geographic data or subset it for a feature code range. Then you have to give the names of the two input geographic files. As indicated by the menu items, the primary geographic file is always a file of polygons while the secodary geographic file is the points or line segments or polygons.

You also have to give a name for the geographic file that will be generated.

You always have to provide a feature code (a positive number) for the generated objects, and can optionally have the feature codes from the intersected (or unioned) pairs of objects included in the new objects.

Polygons are not directly generated. If you intersect or form the union of polygons with polygons the output is line segments which then have to be built into polygons with the zone/polygon building process.
 

SITE LOCATION / ALLOCATION

Introduction

Algorithms are provided to aid in site selection for applications such as the siting of new schools, shopping centres or fast-food outlets.

The facilities are based on ILACS (Interactive Location Allocation in Continuous Space) by Mike Goodchild.
 
 

The selection of a site for some service has two parts:

1. Location of the site.

2. Allocation of the data points to the site.

The data are a set of point locations and attribute data giving the "demand" at each point.

Solutions

There can be up to 5 current solutions, referred to by number. Each provides storage for a complete solution, giving the locations, optional capacities and mobilities of each of the sites

There is always a current solution (initially number one).

The contents of each solution are intially zero, so each site is located at (0,0) with zero capacity and is free to move.

The Alternating and Tornqvist algoriths take the contents of the current solution and place the generated optimum solution into a new, specified current solution.
 

Sites

The storage available for the mattrix of site/demand points is limited, and large numbers of demand points allow smaller numbers of sites to be allocated.

Sites are referred to by name. These are initially SITE001, SITE002 etc, but they can be renamed.

Sites can be mobile or fixed during optimisation; many situations have existing fixed sites and are allocating some new facilities. e.g. the schools in a city may be investigated with the view of keeping most, building a few new ones, and closing some down.

Site locations can be set to random locations within the map area or to a random sample of the data points.

The capacities of the sites can be initialised by dividing the total demand equally among them.

Sites can be located with the cursor / mouse.
 

Geographic Data

A geographic points file gives a set of locations from which the demand is considered to come. Typically the points will be thye centroids of Census polygons. The points are displayed as symbols and any line segments (typically the boundaries of Census district polygons) will also be displayed.

Points should have unique names, but the case of multiple polygons within Census districts (and hence the same name) are handled by dividing the attribute value equally between them.
 

Attribute data

The attribute file gives the demand at the point locations. The data are typically demographic data such as Census data.

The data depend on the application and will often be prepared by applying arithmetic operations to basic attribute data.

In some cases the data are obvious e.g. Census data giving the total population in the age group 11 to 17 years may be used when siting high schools. Other cases may be more complicated and models developed by statistical analysis of other data e.g. an attribute for siting a maternity hospital may be 20% of women aged 17 to 25 years, 25% of women aged 26 to 35 years and 5% of the number of women aged 36 to 45 years. Sometimes a simple attribute may be found to correlate well enough to be used as an indicator variable.

The algorithmns work with positive integer values, so arithmetic operations may have to be used to scale and offset the attribute data. The data values should have a large range.
 

Allocation

An allocation consists of a matrix of assignments of demand from each point to each site. Only one allocation is active at any time.

An allocation is defined explicitly by the allocation operation (the point of Minimum Aggregate Travel using steepest descent) or implicitly by the use of the Alternating or Tornqvist algorithms.
 

Parameters

A number of parameters are used to control operations. They have default values and can be changed during a session.

Barriers and Freeways

Travel limitations such as rivers can be simulated by specifying straight line barriers with the mouse / cursor. Barriers can also be used for other situations such as political boundaries.

Freeways and travel speed ratios can also be specified.
 

Outputs

The current allocation is continually output to a geographic file and displayed. The file name can be changed, and the file can be used for other mapping applications. The file contains: A combine file can be generated giving the points allocated to each site. This can be used to accumulate attribute data for mapping at the sites in the generated geographic file. It could also be used to amalgamate polygons to form territories (if there are no repeated points i.e. weights < 1. In this case you will have to output the combine file as a data file and edit it).

The current allocation can be shown on the screen, and a full report can be output to the usual OZGIS.OUT file.

The allocation can be saved to (and restored from) a file.

Location / allocation example

SITE CATCHMENTS

Introduction

Catchments can be defined as contours around sites and the attribute data extracted from base zones (usually Census data) for mapping.

A common requirement is to know the demographics of an area surrounding a site.

For example, a shopping centre manager would like to know how many customers of a particular type should be attracted to the centre.

The basic source of demographic data is usually Census data. The aim of the site catchment software is to determine weights to be applied to Census districts around a site so values can be accumulated.

As it is expected that the attraction to a site will fall away with distance, the procedure is to define a set of contours around each site.

For example, it may be decided that 95% of people living within 10KM of a hospital will go there in am emergency, 50% within 20KM outside that, and 10% within 30KM.

The contours are defined interactively on the screen, and their shape will reflect other influences such as barriers and competition. For example, the contours may be drawn for a site at location X as:

*

* *

* * *

* * * *

* * X * *

* * * *

* * *

*

After the catchment contours have been defined they can be overlayed on the underlying Census boundaries to find which Census districts lie within each contour. The Census districts, the proportion within the contours and the contour levels are used to produce a list of districts and their weights for each site. The lists are output as a combine file which can be used to amalgamate Census data for mapping.

The site names and locations are output as a geographic file that can be used with the attribute file to map the sites.

Geographic files containing the contour lines and other site definition graphics can also be produced for use as an overlay on maps.

First example

Geographic files

Sites are intiially defined as circles on the ground of a given size. The map projection must be known to do this. The geographic files must be Latitude Longitude with units of degrees.

Census boundary files are usually in this form.

You may have to use the projections options. In particular, even if the file is lat. long. you may have to write that information into the file header by:

Select CHOOSE FROM PROJECTION SET 1 and then GEOGRAPHIC LATITUDE LONGITUDE Then use WRITE PROJECTION DEFINITION INTO GEOGRAPHIC FILE

You will find that the process of intersecting the catchment contours and the base map polygons is slow. As the speed depends on the number of points in the polygons and as the process is approximate it is suggested that the data preparation option be used SIMPLIFY (THIN) LINE SEGMENTS

The catchments are held as latitude / longitude polygons so are independent of the base map i.e. you can use one base map during definition and another during the intersection process. The process assumes an even population distribution across the base map zones, so the smaller the zones the more accurate the results would be.

Note that the current set of sites being processed must always fit on the base map.
 

Catchment files

The system aims to provide facilities for analysis of sites for the definition of site locations and catchments, the retrieval of data, development of models and display of results.

The base of the process is the catchment file.

A catchment file holds the definition of several sites. The sites have some common grouping (e.g. all part of the same retail chain) and all fit on the same base map.

A typical analysis would involve several catchment files, e.g. several sets of sites each for a different organisations( e.g. several sets, each defined on different base maps to increase resolution. )

Site definition is carried out for a current set of sites. These sites can be modified and new sites defined. A base map is always displayed and all the current sites must fit on the displayed map.

Also defined for assistance are any other catchment files relevant to the analysis Site symbols, names and catchments are displayed if they fit on the map. These sites cannot be modified.

A catchment file contains the following information for each site.

Catchment modification

The whole process is iterative with catchments being modified and the results mapped.

The catchment definition menus provide the options (using a displayed base map):

INCLUDE SITES FROM CATCHMENT FILE Enables existing sites to be considered.

ADD A NEW SITE

DELETE A SITE

RENAME A SITE

Provides basic site control.

REPOSITION SITE LOCN, NAME OR SYMBOL Enables shuffling of displayed site information when sites are crowded.

MODIFY SITE CONTOURS Enables several contours to be defined for a site as circles or digitised simple polygons. The contours can reflect the interaction between sites and any barriers.

Contours are essentially simple i.e. they are assumed to be concentric, and do not cross.

CHANGE DISPLAYED REGION Enables zooming and panning of the base map.

TEMPORARILY OVERLAY OTHER CATCHMENT FILE ON BASE MAP Enables other site catchment files to be added as overlays.

OVERLAY GEOGRAPHIC FILES ON BASE MAP Enables lines, points etc to be added to the base map.

INCLUDE POINTS FROM GEOGRAPHIC FILE Enables a set of sites to be defined as circles (all same radius) at locations given in the file.
 

Another example

DIGITAL CHART OF THE WORLD 




Introduction

The Digital Chart of the World (DCW) is a fabulous world-wide database available on 4 CD-ROMs for the cost of distribution.

Points, lines and text data can be imported in VPF format. Polygons can be built from the lines with some restrictions.

The data entry process is designed so only the required files are processed. This means that you do not have to have a CD-ROM drive but can copy the required files from another PC.

Databases

The data comes on four CD-ROMS. Each contains a copy of the world-wide BROWSE library and one other library covering a part of the world You obviously choose which library you want first.

The BROWSE data base contains data files that cover the whole world, but the other detailed libraries contain a hierarchy of file directories of data for 5 degree square tiles.

The first process is finding which directories contain the data you require.

Files

Processing requires two files:

1. a file that contains the actual data

2. A feature attribute table file that defines the feature codes of the

Pairs of files are:

Where xx is the main directory

Utilities

The DCW files are binary. A VPFDUMP program comes with the data and can be used for inspection.

A similar program OZDCW is supplied. This can also be used to inspect data files.

OZDCW must be used to convert the binary DCW files to ascii files in preparation for data input i.e. the raw DCW files cannot be imported. Typing OZDCW FILE will list the file

Hence you often use "OZDCW file | more"

To process a file for importing use e.g. "OZDCW file > dataFile"
 

Coverage directories

The first file to look at is the coverage attribute table at the highest directory level for the library you want. This is called CAT.

e.g. type "OZDCW BROWSE\CAT. | MORE" to find what is in the BROWSE library

Digital Chart of the World file: \usr\local\DCW\BROWSE\CAT.

191L;

Coverage Attribute Table;-;

**DCWcolumns ====================

ID =I, 1,N,Row Identifier,-,-,:

COVERAGE_NAME =T, 8,P,Coverage name,-,-,:

DESCRIPTION =T, 50,N,Coverage description,-,-,:

LEVEL =I, 1,N,Topology level,-,-,:;

**DCWdata ===========================

**DCWrow --------------------

1

CO

ONC Compilation Date

3

**DCWrow --------------------

2

DV

Data Volume

3

**DCWrow --------------------

3

DN

Drainage

3

**DCWrow --------------------

4

GR

Geographic Regions

3

**DCWrow --------------------

5

DA

Hypsographic Data Availability

3

**DCWrow --------------------

6

IN

ONC Index

3

**DCWrow --------------------

7

PO

Political\Oceans

3

**DCWrow --------------------

8

PP

Populated Places

0

Hence Rivers etc are in the drainage coverage, Country boundaries in the

political directory PO etc
 

Directory Contents

Suppose you want to find out the actual data available in the political coverage i.e. the PO directory.

type "OZDCW PO\INT.VDT | more"

Digital Chart of the World file: PO\INT.VDT

252L;

Political\Oceans Integer Value Description Table;-;

**DCWcolumns ====================

ID =I, 1,N,Row Identifier,-,-,:

TABLE =T, 12,P,Name of Feature Table,-,-,:

ATTRIBUTE =T, 16,P,Attribute Name,-,-,:

VALUE =I, 1,P,Attribute Value,-,-,:

DESCRIPTION =T, 50,N,Attribute Value Description,-,-,:;

**DCWdata ===========================

**DCWrow --------------------

1

POAREA.AFT

POPYTYPE

1

Land areas

**DCWrow --------------------

2

POAREA.AFT

POPYTYPE

2

Ocean areas

**DCWrow --------------------

3

POLINE.LFT

POLNTYPE

1

International Boundary

**DCWrow --------------------

4

POLINE.LFT

POLNTYPE

2

Coastline

**DCWrow --------------------

5

POTEXT.TFT

LEVEL

1

Land place names

**DCWrow --------------------

6

POTEXT.TFT

LEVEL

2

Ocean place names

**DCWrow --------------------

7

POTEXT.TFT

LEVEL

3

Ice Status

**DCWrow --------------------

8

POTEXT.TFT

LEVEL

4

Land place names (diacritical)

**DCWrow --------------------

9

POTEXT.TFT

LEVEL

5

Ocean Place names (diacritical)

**DCWrow --------------------

10

POTEXT.TFT

LEVEL

6

Mountain names

**DCWrow --------------------

11

POTEXT.TFT

LEVEL

7

Mountain names (diacritical)

**DCWrow --------------------

12

POTEXT.TFT

LEVEL

8

Island names

**DCWrow --------------------

13

POTEXT.TFT

LEVEL

9

Island names (diacritical)

**DCWrow --------------------

14

POTEXT.TFT

LEVEL

10

Desert names

**DCWrow --------------------

15

POTEXT.TFT

LEVEL

11

Desert names (diacritical)

**DCWrow --------------------

16

POTEXT.TFT

SYMBOL

1

Black annotation

**DCWrow --------------------

17

POTEXT.TFT

SYMBOL

4

Blue annotation

Each entry tells you what it is, the attribute feature table you have to use,

and the feature code e.g. the entry:

**DCWrow --------------------

4

POLINE.LFT

POLNTYPE

2

Coastline

Tells you that to to extract the Coast outline you need feature code 2
 

Example - World Countries

To map the whole world use the BROWSE library.

Some of the files have been provided with OzGIS.

First look at the coverage attribute table, which basically tells what is in the various directories for the library:

Type "VPFdump \usr\local\DCW\BROWSE\CAT. | more"

191L;

Coverage Attribute Table;-;

ID =I, 1,N,Row Identifier,-,-,:

COVERAGE_NAME =T, 8,P,Coverage name,-,-,:

DESCRIPTION =T, 50,N,Coverage description,-,-,:

LEVEL =I, 1,N,Topology level,-,-,:;

1 CO ONC Compilation Date

3

2 DV Data Volume

3

3 DN Drainage

3

4 GR Geographic Regions

3

5 DA Hypsographic Data Availability

3

6 IN ONC Index

3

7 PO Political\Oceans

3

8 PP Populated Places

0

So rivers will be in the DN directory, towns in the PP directory etc.

In this example look at to PO directory...

As before, start by looking at the Integer Value Description table:

type "VPFdump \usr\local\DCW\BROWSE\PO\INT.VDT : more"

252L;

Political\Oceans Integer Value Description Table;-;

ID =I, 1,N,Row Identifier,-,-,:

TABLE =T, 12,P,Name of Feature Table,-,-,:

ATTRIBUTE =T, 16,P,Attribute Name,-,-,:

VALUE =I, 1,P,Attribute Value,-,-,:

DESCRIPTION =T, 50,N,Attribute Value Description,-,-,:;

1 POAREA.AFT POPYTYPE 1 Land areas

2 POAREA.AFT POPYTYPE 2 Ocean areas

3 POLINE.LFT POLNTYPE 1 International Boundary

4 POLINE.LFT POLNTYPE 2 Coastline

5 POTEXT.TFT LEVEL 1 Land place names

6 POTEXT.TFT LEVEL 2 Ocean place names

7 POTEXT.TFT LEVEL 3 Ice Status

8 POTEXT.TFT LEVEL 4 Land place names (diacri tical)

9 POTEXT.TFT LEVEL 5 Ocean Place names (diacr itical)

10 POTEXT.TFT LEVEL 6 Mountain names

11 POTEXT.TFT LEVEL 7 Mountain names (diacriti cal)

12 POTEXT.TFT LEVEL 8 Island names

13 POTEXT.TFT LEVEL 9 Island names (diacritica l)

14 POTEXT.TFT LEVEL 10 Desert names

15 POTEXT.TFT LEVEL 11 Desert names (diacritica l)

16 POTEXT.TFT SYMBOL 1 Black annotation

17 POTEXT.TFT SYMBOL 4 Blue annotation

The major interest is the coast and country boundary lines, given by line feature table POLINE.LFT with the feature column POLNTYPE having values 1=International Boundary or 2=Coastline

We will also extract the major place names, feature code 1.

You need pairs of files; the data goes into a .DAT file and the attribute table file into an OzGIS parameter file: Some of these files have been provided with OzGIS.

First the lines:

OZDCW PO\POLINE.LFT > \mapping\DCWLINE.PRM (where mapping is the directory, say)

OZDCW PO\EDG. > \mapping\DCWLINE.DAT

and the text\points data:

OZDCW PO\POTEXT.TFT > \mapping\DCWTEXT.PRM

OZDCW PO\TXT. > \mapping\DCWTEXT.DAT

Now run OzGIS and import geographic data for two pairs of files DCWLINE and DCWTEXT You select the type of DCWdata being imported (lines and text) and specify the feature codes required (see above).

Then map geographic data. Display DCWLINE lines for feature code 2 (the coast).

Then overlay lines for feature code 1 (the internal country boundaries, and overlay DCWTEXT as names at points.
 

Tiles Example

The detailed libraries contain the data in 5 degree square tiles. Each tile is in a lower level directory. To be inconsistent, the feature table files are still in the top level directories.

Suppose we want to map the Mergui Peninsular area, Latitude about 12N, longitude about 98E.

The first thing you have to do is find which directory contains the data

The Face bounding rectangle table tells the extent of each tile

Type "VPFdump \usr\local\DCW\SASAUS\TILEREF\FBR. | MORE"

239L;

"FBR: Face Bounding Rectangle Table";-;

ID =I, 1,P,Row ID,-,-,:

XMIN =F, 1,N,Minimum X Coordinate,-,-,:

YMIN =F, 1,N,Minimum Y Coordinate,-,-,:

XMAX =F, 1,N,Maximum X Coordinate,-,-,:

YMAX =F, 1,N,Maximum Y Coordinate,-,-,:;

1 -180.000092 -55.000000 180.000000 55.000000

2 45.000008 50.000000 50.000000 55.000000

3 50.000008 50.000000 55.000000 55.000000

4 55.000008 50.000000 60.000000 55.000000

5 60.000008 50.000000 65.000000 55.000000

6 65.000015 50.000000 70.000000 55.000000

7 70.000015 50.000000 75.000000 55.000000

8 75.000015 50.000000 80.000000 55.000000

9 80.000015 50.000000 85.000000 55.000000

10 85.000015 50.000000 90.000000 55.000000

11 -180.000092 45.000000 -175.000000 50.000000

12 25.000004 45.000000 30.000000 50.000000

13 30.000004 45.000000 35.000000 50.000000

14 35.000008 45.000000 40.000000 50.000000

....

229 75.000015 10.000000 80.000000 15.000000

230 80.000015 10.000000 85.000000 15.000000

231 85.000015 10.000000 90.000000 15.000000

232 90.000015 10.000000 95.000000 15.000000

233 95.000015 10.000000 100.000000 15.000000 <<<<<<<<<<<<<

234 100.000015 10.000000 105.000000 15.000000

235 105.000015 10.000000 110.000000 15.000000

236 110.000015 10.000000 115.000000 15.000000

237 115.000015 10.000000 120.000000 15.000000

...

So you need tile number 233. The tile reference attribute table gives the directory.

Type "VPFdump \usr\local\share\DCW\SASAUS\TILEREF\TILEREF.AFT | more"

94L;

Tile Reference Areas;-;

ID =I, 1,P,Row Identifier,-,-,:

TILE_NAME =T, 6,N,Tile Name,-,-,:;

1 \\

2 R\K\12

3 R\K\22

4 R\K\32

5 S\K\12

6 S\K\22

7 S\K\32

8 T\K\12

9 T\K\22

10 T\K\32

11 A\K\11

12 P\K\31

13 Q\K\11

14 Q\K\21

15 Q\K\31

16 R\K\11

...

227 S\G\23

228 S\G\33

229 T\G\13

230 T\G\23

231 T\G\33

232 U\G\13

233 U\G\23 <<<<<<<<<<<<<<<<<< coast

234 U\G\33

235 V\G\13

236 V\G\23

237 V\G\33

238 W\G\13

239 W\G\23

...

So the data are in sub-directory U\G\23

So to extract the required data from the PO (political) coverage you could:

OZDCW PO\POTEXT.TFT > \mapping\DCWTEXT.PRM for text

OZDCW PO\U\G\23\TXT. > \mapping\DCWTEXT.DAT

OZDCW PO\POLINE.LFT > \mapping\DCWLINE.PRM for line data

OZDCW PO\U\G\23\EDG. > \mapping\DCWLINE.DAT

OZDCW PO\POPOINT.PFT > \mapping\DCWPOINT.PRM for point data

OZDCW PO\U\G\23\END. > \mapping\DCWPOINT.DAT

Note that the feature table files can be large. If you are short of disk space you need only extract the part of the file that has the IDs covering those of the data file. For example, if you extract data by say:

OZDCW PO\U\G\23\END. > \mapping\DCWPOINT.DAT

Then the OZDCW program will print out the number of records. If you look at the start of the data file by:

MORE < \mapping\DCWPOINT.DAT

then you can find the ID of the first record.

Suppose the first ID is 1234 and there are 100 records, then you can extract just the required feature data by:

OZDCW -f 1234 -l 1334 PO\POPOINT.PFT > \mapping\DCWPOINT.PRM

The first and last record IDs have to cover the range of the data.

e.g. OZDCW -f 1000 -l 1500 PO\POPOINT.PFT > \mapping\DCWPOINT.PRM

As before you find the feature codes by looking at the INT.VDT file

Type " VPFdump \usr\local\DCW\SASAUS\PO\INT.VDT | more"

279L;

Political\Oceans Integer Value Description Table;-;

ID =I, 1,N,Row Identifier,-,-,:

TABLE =T, 12,P,Name of Feature Table,-,-,:

ATTRIBUTE =T, 16,P,Attribute Name,-,-,:

VALUE =I, 1,P,Attribute Value,-,-,:

DESCRIPTION =T, 50,N,Attribute Value Description,-,-,:;

1 POAREA.AFT POPYTYPE 1 Land

2 POAREA.AFT POPYTYPE 2 Open ocean

3 POAREA.AFT POPYTYPE 3 Polar Ice

4 POAREA.AFT POPYTYPE 4 Pack Ice

5 POAREA.AFT POPYTYPE 5 Shelf Ice

6 POLINE.LFT POLNTYPE 1 International boundary, Dejure

7 POLINE.LFT POLNTYPE 2 International boundary, Defacto

8 POLINE.LFT POLNTYPE 3 International boundary, Dejure and Defacto

9 POLINE.LFT POLNTYPE 4 Administrative boundary, primary

10 POLINE.LFT POLNTYPE 5 Administrative boundary, major

11 POLINE.LFT POLNTYPE 6 Treaty or occupancy line

12 POLINE.LFT POLNTYPE 7 Coastal Closure Line

13 POLINE.LFT POLNTYPE 8 Ocean demarcation Line

14 POLINE.LFT POLNTYPE 9 Ice line

15 POLINE.LFT POLNTYPE 10 Coastline

16 POLINE.LFT POLNTYPE 11 Ice\Water line

17 POLINE.LFT POLNTYPE 12 Seawall

18 POLINE.LFT POLNTYPE 13 International Date Line

19 POLINE.LFT POLNTYPE 88 Connector

20 POLINE.LFT POLNSTAT 1 Definite

21 POLINE.LFT POLNSTAT 2 Approximate boundary or fluctuating coastline

22 POLINE.LFT POLNSTAT 3 Indefinite boundary or u nsurveyed coastline

23 POLINE.LFT POLNSTAT 4 Manmade coastline

24 POLINE.LFT POLNSTAT 5 Undetermined coastline

25 POLINE.LFT POLNSTAT 6 Ice cliff (coastline or ice line)

26 POLINE.LFT POLNSTAT 7 River, when boundary

27 POLINE.LFT POLNSTAT 8 Poly closure line

28 POLINE.LFT POLNSTAT 9 None

29 POPOINT.PFT POPTTYPE 1 Small island

30 POTEXT.TFT LEVEL 1 Land place names

31 POTEXT.TFT LEVEL 2 Ocean place names

32 POTEXT.TFT LEVEL 3 Ice Status

33 POTEXT.TFT LEVEL 4 Land place names (diacri tical)

34 POTEXT.TFT LEVEL 5 Ocean Place names (diacr itical)

35 POTEXT.TFT LEVEL 6 Mountain names

36 POTEXT.TFT LEVEL 7 Mountain names (diacriti cal)

37 POTEXT.TFT LEVEL 8 Island names

38 POTEXT.TFT LEVEL 9 Island names (diacritica l)

39 POTEXT.TFT LEVEL 10 Desert names

40 POTEXT.TFT LEVEL 11 Desert names (diacritica l)

41 POTEXT.TFT SYMBOL 1 Black annotation

42 POTEXT.TFT SYMBOL 4 Blue annotation
 

Polygons

You can build polygons from the line data within OzGIS in the usual way.

However, any polygons that are not complete (closed) will be dropped. This means that polgons around the edge of tiles disappear. In some cases there seems to be additional data which may help e.g. there is not only Coast lines but also coast closure lines.

Within the BROWSE library there is a feature code 9 which gives boundary lines so extract line feature 9 as well as feature 2=coast. You will find that you then get polgons for the whole rectangle (-180,-90) to (180,90). You should however be able to edit the output from OZDCW to throw away the type 9 records that are not required (look for 90.0).
 

You can generate polygons for the world from the lines in the earlier example. There are a few funnies, but enter the POLINES.DAT data with the parameter file DCWLAND.PRM as a geographic file, say temp.geo, and then build the polygons from the line segments. You will need to give the number of line segments / poly as at least 500.

Summary

. select the library (BROWSE, SASAUS etc)

. OZDCW or VPFDUMP the file CAT. to find the directories / coverages

. OZDCW or VPFDUMP the file INT.VDT in the required directories to find the feature codes

. if tiled look at \TILEREF\FBR. and \TILEREF\TILEREF.AFT to find the tile directory . generate data and parameter files for importing into OzGIS with the OZDCW program

TXT. and xxTEXT.TFT for test

END. and xxPOINT.PFT for points

EDG. and xxLINE.LFT for lines
 

Other VPF data

The procedure should work for other databases.

One restriction is that only numeric feature codes are handled. If you want to process databases that use text feature values (e.g. the Digital Nautical Chart) you will have to set up the pairs of files in the usual way, but the edit the .PRM file to change all to text feature vales to numbers.
 

MAP DATA FORMATS

Introduction

The OzGIS system was designed to accept data from external sources.

These data may be supplied in standard formats that are supported by the IMPORT option in the top menu. If not, data will have to be reformatted into one of the system formats before use.

Map objects are identified by 16 character keys e.g. PARIS, NEW YORK, 12345 Where keys are generated within OzGIS they are usually left aligned numbers.

OzGIS data Formats

Every type of file has a standard format within OzGIS.

The data files have been designed with a simple format which can be easily generated on computer systems. Most data are held as character files so that they can be generated by programs with, for example, database system export procedures, formatted FORTRAN write statements, or by a text editor. The record lengths are up to 80 bytes long.

Each file starts with a comment record of up to 80 characters, which should be used to hold a meaningful description of the file. The OzGIS system will display this comment when data files are interrogated, so it is in your interest to make the comments meaningful. This record must contain at least one non-blank character.

Data values are entered in record fields that are multiples of 10 bytes.

The following computer restrictions apply:

The maximum numbers of some data items that can be handled are system parameters.

Description of File Formats

The formats for describing the data files in the following sections are similar.

The number of bytes in the field is given at the start of the line. If there are several values in a format, this condition is indicated differently (e.g. 8 x 10 implies eight fields of 10 bytes).

The information on the next line is the type of data in a field:

ATTRIBUTE DATA FORMATS

Preprocessing

Attribute data are often obtained from Census Bureaux. These data are seldom what is required, so will need processing before use.

Data often need normalising to allow for the differences in zone sizes. This is done by arithmetic operations where new attributes are derived by dividing by total population, area etc.

Also, data often need amalgamation e.g. census age groups to get the required group.

OzGIS Standard Format

Attribute files contain the attribute value of each zone or line or site for a number of attributes. The names must correspond to those defined in a geographic file.

The attribute description is used by OzGIS as a heading in a map displaying the attribute. The units description is used by OzGIS as a heading to the class values in the map legend.

For efficient use of the system and to facilitate disc file management, files should contain as many attributes as possible (to avoid having separate files for each attribute).

Attribute files will usually be prepared by special programs which extract data from a data-base and convert attribute values into the OzGIS format.

Comment Record:

80 byte comment describing the data

Header Record:

10 integer number of attributes

10 integer number of names

10 real value used to indicate missing data

Name Records:

8 x 20 byte names, sorted into ascending order (Only first 16 characters are used).

Sets of records follow to define the attributes:-

Definition Record:

30 byte attribute description

10 byte units description

Values Records:

8 x 10 real attribute values for zones, lines or sites in name

order
 

Sample standard attribute file DEMOATTR.DAT

DEMOATTR.DAT - ATTRIBUTES FOR SIMPLE 3 ZONE TEST MAP

5 6 -9.9

ABCDEFGHIJZONE 1 ZONE 2 ZONE 3 ZONE 4 ZONE Z

FIRST STATISTIC FIRST UNITS

1.0 2.0 3.0 4.0 5.0 6.0

SECOND STAT SECOND UNITS

100.0 200.0 -9.9 400.0 500.0 600.0

THIRD STAT 3RD UNITS

0.1 0.9 0.3 0.7 0.1 0.8

FOURTH STATS 4TH UNIT

1.0 2.0 3.0 3.0 2.5 1.5

FIFTH STAT 5TH UNIT

9.0 6.0 3.0 2.0 6.0 8.0

Simple Attribute format (tabular database format)

Many data retrieval systems (e.g. ORACLE,SAS) produce attribute data in a form where for each attribute the names and their values are given.

This tabular format is supported in OzGIS although there are some restrictions on its use. The list of names is obtained from the first attribute; hence no new names can occur in following attributes (although names may be missing). A set of data records for an attribute is assumed to finish (and the next set start) when the attribute description & units changes.

Comment record:

80 byte Comment describing the data

Data records:

20 byte name

10 real value

30 byte attribute description

10 byte attribute units
 

Sample simple attribute file DEMOSASA.DAT

SIMPLE FORMAT ATTRIBUTE FILE - DEMOSASA.DAT

TOP 1.0 DESCRIPTION A UNITS A

SQUARE 2.0 DESCRIPTION A UNITS A

DIAMOND 3.0 DESCRIPTION A UNITS A

TRIANGLE 4.0 DESCRIPTION A UNITS A

TOP 1.0 DESCRIPTION B UNITS B

DIAMOND 3.0 DESCRIPTION B UNITS B

SQUARE 2.0 DESCRIPTION B UNITS B

TRIANGLE 4.0 DESCRIPTION B UNITS B

TOP 1.0 DESCRIPTION C UNITS C

SQUARE 2.0 DESCRIPTION C UNITS C

DIAMOND 3.0 DESCRIPTION C UNITS C

TRIANGLE 4.0 DESCRIPTION C UNITS C

TOP 1.0 DESCRIPTION D UNITS D

TRIANGLE 4.0 DESCRIPTION D UNITS D

DIAMOND 3.0 DESCRIPTION D UNITS D

DIAMOND 3.0 DESCRIPTION E UNITS E

TRIANGLE 4.0 DESCRIPTION E UNITS E
 

Spreadsheet WK1 format (Lotus, Excel etc)

The WK1 file format is used to import/export data between OzGIS and spreadsheet and database systems. Refer to the chapter on the WK1 interface to systems.

Data from spreadsheets can be input in Lotus 1-2-3 format (WK1).

The spreadsheet must be set up in a fixed format:

The data values are in a matrix with the values for the zones (or sites or lines) in columns and the different attributes across in the rows.

Values can be missing and can be integer or floating point.

The first column must contain labels which are the 10 character zone (site etc) names, beginning at row 3. These must be SORTED in ascending order.

The top row contains labels that are the (up to) 30 character attribute descriptions starting at column 2.

The second row is the 10 character attribute descriptions. This is recommended but does not have to be present as some systems (e.g. MS ACCESS) do not allow units to be defined.

e.g. the file DEMO123.dat can be read into the spreadsheet. It should look like:
 
GROWTH SALES
NUMBER $
ABBOTSFORD 7418 237
BURWOOD 9925 955
CONCORD 8984 202
CROYDON 9369 298
CROYDON W 735
FIVEDOCK 9903 716
HABERFIELD 727
HOMEBUSH 6631 704
HUDSONPARK 4668 71
MORTLAKE 1725 198
STRATHFIELD 6285 663
YARALLA 9875 516

For example, with Microsoft Excel for Windows, the test file can be read by choosing the option "Open" from the "File" menu and giving the test file as \OZDEMO\DEMO123.DAT. A spreadsheet in the above format can be output by selecting the "Save As" option from the "Files" menu and using the WK1 format option.
 

ATLAS Data files

Attribute data files for the Atlas mapping system come as pairs of files, a format file and a data file.

The first record of the format file is a map name, which is ignored. There follows a a set of records, each of which gives the name of an attribute. For example, the following file specifies two attributes:

" Bundesland$"

"Population 1984 Totale Population in Tausend"

"Ausdehnung in qkm Ausdehnung in Quadratkilometer"

The data files have one record for each map item. Each record starts with the item name, and is followed by the values. The values are in the same order as the attribute names and there is one per attribute (2 here). Values can be in integer, decimal point or exponential formats. A value of 1.0E36 is missing data. For example:

"SCHLES.-HOLSTEIN", 2615 , 157.21

"HAMBURG", 1.23E21 , 1.0E36

"BREMEN", 671 , 404

"NIEDERSACHSEN", 7230 , 47.447

"NORDR.-WESTFALEN", 16.777 , 34061

"HESSEN", 5548 , 21114

"RHEINLAND-PFALZ", 3627 , 198.48

"SAARLAND", 1052 , 25.71

"B.-WUERTTEMBERG", 9240 , 35751

"BAYERN", 10964 , 70552

"BERLIN", 1850 , 480

Names and attribute descriptions must be delimited by apostrophes as shown, and values must be comma delimited. Only the first 16 characters of a zone etc name is used and only the first 30 characters of a description.

Two data files have to be specified. The first is the format file, the second the Atlas data file. The format file is handled as a parameter file within the entry process so can be present on disk as a file named with extension .PRM. In practise your two files will probably have the Atlas standard file names with extensions FMT and DAT and you give the full file names when asked for them.

For example, you might have a pair of files named EUROPE.FMT and EUROPE.DAT so you give the parameter file as EUROPE.FMT and the data file as either EUROPE or EUROPE.DAT (as DAT is the default extension).

LAMM format

The LAMM package was developed at the CSIRO Division of Building Research. The format is supported as it is the only suitable format for mapping available in the Australian Bureau of Statistics GEOSTATS system.

The first record gives the number of map items and the number of attributes respectively.

The attribute names follow, one per record

Finally the value records are given, being the name followed by the values.

The records are sorted into ascending name order. Values are separated by blanks or commas.

An example file is DEMOLAMM.DAT:

12,8

MALES 35 - 44 (81)

MALES 35 - 44 (86)

MALES - UNEMPLOYED (76)

MALES - UNEMPLOYED (81)

MALES - UNEMPLOYED (86)

INCOME MALES $18001-$26000 (76)

INCOME MALES $18001-$26000 (81)

INCOME MALES $18001-$26000 (86)

'ABBOTSFORD' 69 0 14 27 48 0 51 55

'BURWOOD E' 223 0 48 134 89 0 218 397

'CONCORD' 102 0 5 12 29 0 109 197

'CROYDON N' 161 0 27 50 53 0 156 284

'CROYDON W' 180 0 24 36 76 0 307 241

'FIVE DOCK' 50 0 20 2 0 0 19 11

'HABERFIELD' 126 0 28 20 20 0 208 185

'HOMEBUSH' 114 0 26 51 37 0 165 212

'HUDSONPARK' 243 0 65 99 65 0 231 385

'MORTLAKE' 0 0 0 0 2 0 0 113

'STRATHFIELD' 100 0 4 7 10 0 74 70

'YARALLA' 7 0 16 2 0 0 4 3
 

Comma delimited format

The comma delimited format consists of a set of records: Each record has a series of values separated by commas.

The first record gives the "column" names. The first is the map item names, and the others are the attribute descriptions.

The following records are the data:

The first value is the item (zone,line or site) name and there follows one number for each attribute.

The file DEMOCOMD.DAT looks like:

"ZONE","DOGS","CATS","BIRDS","RATS","FISH","HENS","SNAKES","COWS"

"Australia",1,0,0,0,36,40,0,400.123

"Europe",123.45,0,4,3,47,70,3,0

In many cases the best procedure is to read comma delimited formats into your spreadsheet, convert them into a sensible format, and output them in WK1 format as above.
 

Australian 1991 Census format

The Community profile floppy disk software from the ABS generates comma delimited files that are the same as the above comma delimted format except for an extra (second) column that gives a description for the Census regions. The software drops the extra column. See the sample file ABSCOMMA.DAT
 

Other attribute data formats

Other formats will be supported as required.

We will support any formats for major data suppliers, but you must send sample data and documentation.

We will also attempt to support file formats from other packages.

Text Attribute files

Text attribute files allow miscellaneous information to be attached to map items and accessed during map interrogation

The file format is:

The first record is an 80 character comment

Sets of records follow for each map item:

The item name (1-16 characters) preceded by $

Any number of lines of text (up to 80 characters long)

The $ indicates the start of a new item

An example file is DEMOTEXT.DAT

A file could look like:

SALES TERRITORY DEFINITIONS

$Terr 1

North West NSW

Fred Smith

1991 Target $200,000

$Terr 2

Central Queensland

Salley Jones

1991 Target $320,000

$Terr 3

Tasmania

The Big Bopper

1991 Target $10,000

OzGIS GEOGRAPHIC FORMAT 




General Information

The standard data format reflects the internal topological file structure.

In practice, a complete data file is seldom available. It is more common to bring in just points (as a map and points partition) or lines (as a map and segments partition). Zones are usually formed from the segments by using the zone/polygon building process. Coordinates are usually given either in degrees (for lat,long) or in metres / feet for UTM.

Structure of data

Geographic files contain several partitions. The first must be the map partition, and can be followed by at most one of each of zones, polygons, lines, segments and points partitions.

Each partition is preceded by a type record, which is one of MAP, ZONES, POLYGONS, LINES or POINTS; for example, a zones file must have the following structure:

Comment record

MAP

map records

POLYGONS

polygon records

ZONES

zone records

SEGMENTS

segment records

Different partitions are present (the MAP partition is always first) according to the type of data:-

Files which describe zones have a ZONES partition to define the zones, a POLYGONS partion to give the polygons that bound each zone (including lakes and islands), and a SEGMENTS partition to define the coordinate points that draw the segments along the polygon boundaries.

Sites files have a POINTS partition to give the site names and locations.

Lines files have a LINES partition to define the line names and a SEGMENTS partion to define the coordinate points in the segments that make up the lines.

Line overlays are defined by SEGMENTS partitions.

Marker and name overlays are defined by POINTS partitions.

Coordinate data should be entered in standard units. Coordinate pairs are always in the order (X,Y) (e.g. (Longitude, Latitude)). Note that latitude must be entered as a negative number in the Southern Hemisphere.

Data entered in latitude-longitude projection can be converted to other projections.

Feature codes may be included to give a classification of geographic items. e.g. segments may be classified as different types of roads.

All geographic regions (windows) are given in actual coordinate values in the order: X-minimum, X-maximum, Y-minimum, Y-maximum.

Internal Data

The geographic data are held internally as a word-addressable random access disk file.

The file structure reflects the data structure with the necessary indexing etc for processing.

Additional data are also generated for efficient processing:-

Format

Comment Record

80 byte comment describing the data
 

Map Partition

This partition contains general information about the file (map) and must be the first partition.

Type Record:

3 byte partition header = MAP

Window Record:

4 x 10 real the region covered by the file

Projection Record: (now redundant)

10 integer Map projection code

0=none, 1=lat-long degrees

10 integer type of zones (optional)

10 integer tolerance for joining line segments endpoints into

polygons. Values range 0-3, usually zero

Used when endpoints calculated by spatial operations

e.g. polygon intersection, when arithmetic roundoff

can cause joining to fail
 

Zones Partition

This partition defines the zones in the geographic region.

Each zone is defined by one or more polygons. A zone may consist of a polygon, several separated polygons, polygons with interior polygons of other zones, etc.

If a zones partition is present, a polygons partition with the referenced must be given.

The partition may be used as a polygon underlay and feature codes may be used to give a classification e.g. the polygons may be different soil types.

Type Record:

5 byte partition header = ZONES

Definition Record:

10 integer number of zones

10 integer number of feature codes

Feature code Records (if required):

8 x 10 integer feature codes

Zone Records:

20 byte zone name, usually left justified, blank filled

10 integer number of polygons in the zone

Polygon Records:

8 x 10 integer identifying numbers of the polygons

Line Partition

The partition defines networks of lines (e.g. roads, rivers). Each network has a name and is specified in terms of line segments.The name can be used to apply quantised attribute data.

Type record:

5 byte partition Leader = LINES

Header record:

10 integer number of lines

Line record:

20 byte line name, usually left justified, blank filled

10 integer number of segments forming the line

Region Record:

4x10 real line limits (window)

X minimum, X-maximum, Y-minimum, Y-maximum)

Segments Records:

8x10 integer the identifying numbers of the line segments.

Polygons Partition

A polygon defines an enclosed geographic area. Each polygon is specified in terms of the line segments which constitute its boundary. If a zones partition is given, every polygon referenced by the zones must be defined.

The centroid or internal point of a polygon is be used by OzGIS to locate text (zone names) or graphic symbols; a points partition is generated.

Type Record:

8 byte partition header = POLYGONS

Header Record:

10 integer number of polygons

A set of records follow for each polygon:-

Definition Record:

10 integer polygon identification number

20 byte name of zone enclosed by polygon

10 integer number of lines forming the polygon boundary

10 integer level of polygon for display using

polygon fill 0=standard, 1=lakes, 2=islands in lakes etc. (range 0-5)

Region Record:

4 x 10 real polygon limits (window)

(X-minimum, X-maximum, Y-minimum, Y-maximum)

2 x 10 real centroid or labelling point (X,Y) in the polygon (set to centre of window if not given)

10 real area of polygon

(calculated if not given)

Segments Records:

8 x 10 integer the identifying numbers of the segments + ve if segment is clockwise, -ve if anticlockwise.

Segments Partition

Line segments are defined by a set of points connected by straight lines.

Segments may define the boundaries of zones, define line networks, or line overlays.

When a segment is a boundary segment of a polygon, it can be the boundary of at most two polygons.

In other words, the polygons must be a unique tessellation of the geographic region.

When the segments define polygon boundaries, the partition should contain only the segments of the polygons, and the records must contain the names of the zones on each side. Left and right zones are defined by the direction implied by the sequence of points in the line. The zone names must correspond to those defined in the zones partition. The special zone name OUTSIDE (left aligned) should be used when the line is at the edge of the map, or on the boundary of void areas.

Line segments (of polygons) must be closed (i.e., the last point in a segment must be the first point of another segment), and segments must not cross or have loops. Further, segment must not be repeated.

Segments that are to be used as geographic overlays may have feature codes to give a classification e.g. different types of rivers.

Address information can be present. This consists of the name of the street followed by 0, 1 or 2 sets of entries for street number ranges and postal codes. These zip codes are optional as are the number ranges. If 2 ranges are given one is odd and the other even numbers. The start and end values are given according to the direction of the numbers and the digitising direction.

Type Record:

8 byte partition header = SEGMENTS

Header Record:

10 integer number of segments

A set of records follows for each segment.

Definition Record:

10 integer identifying number

20 byte name of left zone (if line is part of a zone boundary)

20 byte name of right zone (if line is part of a zone boundary)

10 integer number of points in segment

10 integer number of feature codes

10 byte non blank indicates that address info follows

20 byte name of line network, default set to ldent number

this is also the name for interrogation

Feature code Records (if required):

8 x 10 integer feature codes

Address Records (if required):

20 byte name of street, park etc

6 x 10 integer start number, end number, postal (ZIP) code, followed by optional second set

Point Records:

8 x 10 real (X,Y) coordinate pairs (4 per record)

Points Partitions

The partition contains a set of points or sites at which symbols can be overlayed on the map. The site name can be used to apply quantised attribute data or used to annotate the points.

Feature codes can define a classification for display as sites.

Type Record:

6 byte partition header = POINTS

Header Record:

10 integer number of points

Point Records:

10 real X-coordinate value

10 real Y-coordinate value

40 byte site name or annotation

10 integer number of feature codes

Feature code Records (if required):

8 x 10 integer feature codes

Note that only the first 16 characters are used for the site name.

Sample boundaries geographic file DEMOZSEG.DAT

Geographic data for zones (e.g. Census districts) are usually brought in as the line segments that form the boundaries of the zones. The boundary segments contain the (X,Y) vertices that make up the line and the names of the zones on each side of the line.

These data are usually entered via the IMPORT option in the top menu, then excessive vertices discarded (thinned) using PREPARE DATA FOR DISPLAY, and then the full zone / polygon/ line segment / centroids structure built using BUILD TOPOLOGY FROM LINES SEGMENTS to prepare for display.

For example, to extract ZIP code boundaries from USA TIGER files, the left and right ZIP codes are extracted from the records and formed into left aligned zone names, and the latitude / longitude vertices are also extracted. If the left and right zone names are the same the segments are internal to the zone and can be ignored.

The following illustrates the standard format used to enter such data. Note that the MAP partition is required but that the extent need not be given.

EXAMPLE ZONE BOUNDARY SEGMENTS THAT CAN BE BUILT INTO ZONES - DEMOZSEG.DAT

MAP

0.0 0.0 0.0 0.0

0

SEGMENTS

10

107ZONE 1 OUTSIDE 2

102.00 503.00 114.00 503.00

125ZONE 2 ZONE 1 2

102.00 503.00 110.00 513.00

143ZONE 1 ZONE 3 2

114.00 503.00 110.00 513.00

161ZONE 3 OUTSIDE 6

114.00 503.00 115.00 505.00 116.00 507.00 117.00 509.00

118.00 511.00 119.00 513.00

187ZONE 2 ZONE 3 2

110.00 513.00 119.00 513.00

205ZONE 2 OUTSIDE 4

119.00 513.00 114.00 518.00 109.00 517.00 104.00 516.00

227ZONE 2 OUTSIDE 2

104.00 516.00 110.00 513.00

245SURPLUS SURPLUS 2

119.00 513.00 122.00 506.00

263OUTSIDE ZONE 2 2

103.00 509.00 110.00 513.00

281OUTSIDE ZONE 2 2

    503.00 103.00 509.00

Sample segments file with addresses DEMOADDR.DAT

Address information can be added to line segments. Note the non-blank flag.

EXAMPLE SEGMENTS (ROADS) WITH ADDRESSES - DEMOADDR.DAT

MAP

0.0 0.0 0.0 0.0

0

SEGMENTS

10

107ZONE 1 OUTSIDE 2 ADDRESS

Great North Road

1 666 2600

102.00 503.00 114.00 503.00

12 ZONE 1 2 ADDRHERE

Molonglo Gorge

102.00 503.00 110.00 513.00

143ZONE 1 ZONE 3 2 address

Burra Street

1 99 6 140

114.00 503.00 110.00 513.00

161 6 address

Northbourne Ave

1 55 2602 20 66 2600

114.00 503.00 115.00 505.00 116.00 507.00 117.00 509.00

118.00 511.00 119.00 513.00

187ZONE 2 ZONE 3 2

110.00 513.00 119.00 513.00

205 4 address

Yass rd

1 99 2600

119.00 513.00 114.00 518.00 109.00 517.00 104.00 516.00

227ZONE 2 OUTSIDE 2

EPPING HWY

44 22 77 11

104.00 516.00 110.00 513.00

245SURPLUS SURPLUS 2 address

Hume Highway

1 99 2301 88 44 2304

119.00 513.00 122.00 506.00

263OUTSIDE ZONE 2 2 address

Mains Avenue

1 99 2600 6 140 2600

103.00 509.00 110.00 513.00

281OUTSIDE ZONE 2 2 address

Lover's Lane

33 11

    503.00 103.00 509.00

Sample zones geographic file DEMOZONES.DAT

The full topological geographic structure can be entered (although in practice this is seldom available).

COMMENT LINE FOR TEST DATA - DEMOZONE.DAT

MAP

102.00 122.00 502.00 518.00

0

ZONES

3

ZONE 1 1

352

ZONE 2 2

377 402

ZONE 3 1

327

POLYGONS

4

327ZONE 3 3 0

110.00 119.00 503.00 513.00 114.00 510.00

187 -161 143

352ZONE 1 3 0

102.00 114.00 503.00 513.00 108.00 506.00

-125 107 143

377ZONE 2 3 0

102.00 110.00 503.00 513.00 104.00 508.00

-263 -281 125

402ZONE 2 3 0

104.00 119.00 513.00 518.00 110.00 515.00

205 227 187

SEGMENTS

10

107ZONE 1 OUTSIDE 2

102.00 503.00 114.00 503.00

125ZONE 2 ZONE 1 2

102.00 503.00 110.00 513.00

143ZONE 1 ZONE 3 2

114.00 503.00 110.00 513.00

161ZONE 3 OUTSIDE 6

114.00 503.00 115.00 505.00 116.00 507.00 117.00 509.00

118.00 511.00 119.00 513.00

187ZONE 2 ZONE 3 2

110.00 513.00 119.00 513.00

205ZONE 2 OUTSIDE 4

119.00 513.00 114.00 518.00 109.00 517.00 104.00 516.00

227ZONE 2 OUTSIDE 2

104.00 516.00 110.00 513.00

245SURPLUS SURPLUS 2

119.00 513.00 122.00 506.00

263OUTSIDE ZONE 2 2

103.00 509.00 110.00 513.00

281OUTSIDE ZONE 2 2

102.00 503.00 103.00 509.00
 

Sample lines geographic file DEMOLINES.DAT

A lines structure is used for line data that is to be displayed for attribute data. Each line can be made up of several segments:

SAMPLE LINE NETWORK DATA DEMOLINES.DAT

MAP

103.50 121.50 503.50 517.50

0

LINES

4

ROAD 3 3

110.50 119.50 503.50 513.50

187 161 143

ROAD 1 2

103.50 114.50 503.50 513.50

125 107

ROAD 2 2

103.50 110.50 503.50 513.50

263 281

ROAD 4 2

104.50 119.50 513.50 517.50

205 227

SEGMENTS

9

107 2 0 ROAD 1

103.50 503.50 114.50 503.50

125 2 0 ROAD 1

103.50 503.50 110.50 513.50

143 2 0 ROAD 3

114.50 503.50 110.50 513.50

161 6 0 ROAD 3

114.50 503.50 115.50 505.50 116.50 507.50 117.50 509.50

118.50 511.50 119.50 513.50

187 2 0 ROAD 3

110.50 513.50 119.50 513.50

205 4 0 ROAD 4

119.50 513.50 114.50 517.50 109.50 517.50 104.50 516.50

227 2 0 ROAD 4

104.50 516.50 110.50 513.50

263 2 0 ROAD 2

103.50 509.50 110.50 513.50

281 2 0 ROAD 2

103.50 503.50 103.50 509.50

Sample points geographic file DEMOPOINT.DAT

Points files just give the (X,Y) locations and a site name / label.

These files can be used with an attribute file for mapping site data or can be used to place sysmols or labels at locations (overlays).

COMMENT LINE FOR TEST DATA - DEMOPOINT.DAT

MAP

102.00 122.00 502.00 518.00

0

POINTS

3

114.0 503.0 PNT1

104.0 516.0 PNT2

    518.0 PNT3

GEOGRAPHIC POLYGON FORMATS

SAS Format Zone Files

The SAS system provides a crude polygon format for map data. The old format has been updated to allow for multiple polygons in zones and for data at several levels of resolution.

The polygons must be given in the correct order for display when there are polygons within other polygons.

The data consists of variable length records with the following fields:

field1: the zone name

field2: the polygon number within the zone (usually 1)

field3: the X value

field4: the Y value

For example, part of a file might be as follows, where zone 19 has 2 polygons

17 1 135.0198593289 -45.006152242

17 1 135.0214474499 -45.008039698

17 1 135.0234586746 -45.011447966

17 1 135.0232417881 -45.011781529

17 1 135.0146185011 -45.012796119

17 1 135.0149845481 -45.012392245

17 1 135.0148004219 -45.011233956

17 1 135.0155192316 -45.009236805

17 1 135.0140719935 -45.006661419

19 1 135.0200279355 -45.018230647

19 1 135.0211774409 -45.018684313

19 1 135.0218305141 -45.017554402

19 1 135.023555249 -45.017326832

19 1 135.024860993 -45.014845043

19 1 135.0251943022 -45.014588848

19 1 135.0192894787 -45.023670658

19 1 135.0179009587 -45.022158593

19 1 135.0182676911 -45.021624267

19 1 135.0180351585 -45.020997345

19 1 135.0192095339 -45.020121485

19 1 135.0194375813 -45.01857923

19 2 135.0279172212 -45.023049563

19 2 135.0281361789 -45.022784472

19 2 135.0283748209 -45.0230802

19 2 135.0285159498 -45.022607252

19 2 135.0283438861 -45.023600549

21 1 135.041364044 -45.0087376237

21 1 135.039871216 -45.0095451251

21 1 135.039485425 -45.0093839765

21 1 135.037185282 -45.0106722265

.

.

.

.

.

Simple Format (old SAS) Zone Files

Simple format files are in common use by the SAS system and other packages providing SAS interfaces. Polygon for lakes etc. should follow standard polygons to provide the correct display order for overwriting.

This format has now been updated in the SAS system.

Each data record has the form

20 byte zone name

10 real X coordinate

10 real Y coordinate

10 integer Polygon number within zone

Sample simple zones data file DEMOSASG.DAT

SQUARE 3.0 5.0

SQUARE 7.0 5.0

SQUARE 7.0 10.0

SQUARE 3.0 10.0

DIAMOND 8.0 8.0

DIAMOND 10.0 5.0

DIAMOND 12.0 8.0

DIAMOND 10.0 11.0

TRIANGLE 13.0 5.0

TRIANGLE 16.0 10.0

TRIANGLE 19.0 5.0

TRIANGLE 13.0 2.0 2

TRIANGLE 15.0 2.0 2

TRIANGLE 14.0 4.0 2

SQUARE 4.0 0.0 2

SQUARE 8.0 0.0 2

SQUARE 8.0 4.0 2

SQUARE 4.0 4.0 2

SQUARE 0.0 0.0 2

SQUARE 5.0 1.0 2

SQUARE 5.0 3.0 2

SQUARE 7.0 3.0 2

SQUARE 7.0 1.0 2

OUTSIDE 15.0 6.0 2

OUTSIDE 15.0 7.0 2

OUTSIDE 17.0 7.0 2

OUTSIDE 17.0 6.0 2

TOP 4.0 8.0

TOP 19.0 8.0

TOP 19.0 9.0

TOP 4.0 9.0

OTHER GEOGRAPHIC DATA FORMATS

TIGER

The US Census boundaries are distributed in the TIGER format. Most of the data are available on the NET along with lots of documentation.

The data comes as several files which have different extensions where the last digit of the file name (extension) varies. To enter data you give any file as input and the names of the files required are formed from that name.

OzGIS uses the files with names ending in 1, 2, 3, 6, and 7 depending on the type of data required.

See the chapters on US Census data.

DIME format

This format is supported, but has not had much use. The data are primarily 2 point segments, so is inefficient on storage.

Note that only 499 2 point segments can be handled.

The data are usually passed through BUILD ZONES?POLYGONS to build polygons and then through PREPARE DATA FOR DISPLAY to join up the segments into ones of decent length.

The data are long Ascii records, and look something like:

XX91609160012583 1

MANUEL ST 8 8 201 299 200

29891600000011 14502 1450219711197119160 38 440195019510003016 234

10003016 213 1818 396750 757476396740

7574760610215040685606098370406849

MANUEL ST 8 8 301 359 300

35891600000029 14502 1450219711197119160 44 480195019510003016 233

10003016 212 1818 396740 757476396730

7574760609837040684906095020406848

MANUEL ST 8 8 361 399 360

39891600000037 14502 1450219711197119160 48 540195019510003016 233

10003016 233 1818 396730 757476396718

7574760609502040684806090470406846

SCHOOL ST 9 9 900 998 901

99991600000045 162 162 19720197209160 37 220200020010003031 107

10003031 108 1818 396611 755737396619

7557430605026045580006053140455632

SCHOOL ST 9 9 1000 1098 1001

109991600000052 162 162 19720197209160 22 140200020010003031 115

10003031 115 1818 396619 755743396624

7557460605314045563206054910455542

DLG optional 3 format

The DLG-3 format is the major interchange format in use, and data can be obtained from many mapping agencies e.g. from USGS.

The data differs in concept from the usual data displayed by OzGIS in that it is preclassified by the assignment of numeric "feature codes".

All identifiers are numbers. These are converted to names by left aligning them in the 10 character name fields.

The data entry process processed the lines only. Any line with one vertice or two vertices and the same node numbers is taken as a point.

Other lines are output with the left and right names set to the area names. Left and right area numbers of zero or one are taken to be outside the map.

Feature codes are stored as numbers (combined input pairs) for lines, points and zones e.g. '291 22' becomes 2910022.

The first area is ignored as it should be the boundary of the map.

Polygons are generated by passing the geographic file through the zone building process. This carries the area feature codes through to the polygons, retains the line segments, and forms a points segment that contains the centroids of the polygons.

Note that file should have 80 character fixed length records. In practise files often have no end-of-records (e.g. USGS CD-ROM files) or records may be truncated. Records with end-of-line markers must no be more than 80 characters long. Zero length records are not allowed.

You will find that DLG-3 files off ARC-INFO systems often have extraneous background polygons that "zap" the map when displayed.

Some test files are supplied for Hawaii. These were read off the USGS GeoDATA CD ROM on a SUN system, and 'newline' characters inserted to form 80 character records. The files had to be edited as an arbitrary polygon was given as outside the map as the left and right areas on the line (this could also be handled during display by specifying feature codes).

The test files are:

The data format is described in the US Geological Survey Circular 895-c "USGS Digital Cartographic Data Standards, Digital Line Graphs"

The files look like:

USGS-NMD DLG DATA - CHARACTER FORMAT - 09-29-82 VERSION s21_wb.dlg

HAWAIIAN ISLANDS POLY 10 DROPPED 1967, 1980 2000000.

this record not used, cant be zero length

3 3 9999 2 0.50800000000D+02 4 0 4 1

0.637820640000000D+07 0.676865799729109D-02 0.800000000000000D+07

0.180000000000000D+08 -0.157000000000000D+09 0.300000000000000D+07

0.0 0.0 0.0

0.0 0.0 0.0

0.0 0.0 0.0

0.10000000000D+01 0.0 0.0 0.0

SW 19.000000 -160.000000 -316386.41 1771715.66

NW 22.000000 -160.000000 -312489.03 2102112.53

NE 22.000000 -155.000000 208312.61 2101093.98

SE 19.000000 -155.000000 210917.63 1770684.40

WATER BODIES 0 74 74 010 12 12 010 70 70 1

N 1 -316386.41 1771715.66 0 0 0

N 2 -312489.03 2102112.53 0 0 0

N 3 208312.61 2101093.98 0 0 0

N 4 210917.63 1770684.40 0 0 0

.

.

.

.

N 74 -320966.08 2105481.92 2 0 0

-69 70

A 1 -68438.87 1949336.24 3 0 1 0 0

8 9 7

0 0

A 2 -327997.34 2094827.63 3 0 1 0 0

-10 -2 -1

40 150

.

.

.

.

A 13 -91708.84 2025480.45 3 0 1 0 0

-66 -65 -67

40 150

L 1 7 6 2 0 24 1 0

-332906.23 2078428.77 -332805.62 2077920.57 -331991.53 2078579.38

-332446.45 2079748.67 -331479.96 2080407.19 -331224.96 2080914.69

-331578.38 2082032.98 -331221.19 2082845.09 -330100.11 2084620.90

-329235.22 2085279.61 -328573.03 2086192.72 -328571.24 2087107.12

-327247.56 2088577.74 -325977.26 2088727.66 -325164.16 2088878.47

-324909.37 2089284.37 -324503.57 2088978.78 -323182.17 2089280.99

-322319.07 2089025.30 -321707.68 2089938.51 -321250.68 2089836.02

-320995.88 2090241.92 -319775.79 2090696.74 -318961.20 2091609.55

290 4000

.

.

.

.

L 70 74 66 11 0 2 1 0

-320966.08 2105481.92 -321422.78 2105736.82

290 4002

Gina format

The standard interchange format for GeoVision GIS is Gina.

Only some of the data file is processed. Feature codes must be numeric. Zone names generated are of the form ZONE12345 and site names are of the form POINT12345.

Only boundary lines and points are output - you have to generate the zones / polygons afterwards.

The sample file DEMOGINA.DAT is as follows:

udb-start b v 8192

udb-header 0.5 fred-db "Fred's test database"

descr 29oct85 14:32:10 example GINA files

coord-sys rect feet

extent -12000, -8000, 12000, 8000

layer 1 base "base information layer"

layer 2 roads "roads and streets layer"

layer 3 hydro "hydrographic layer (rivers, streams etc)"

layer 4 telephone "telephone plant layer"

layer 5 lots "property lots layer"

network 1 emergency l 2 "emergency routes"

network 2 property p 5 "property polygon network"

udb-primary

table road free

field name char 40 i n "road name"

field r_type char 12 i n "type of road, arterial, highway etc"

field lanes num 2,0 "maximum number of lanes"

field surface char 10 n "type of surface"

fc 1000, 1099

table house free

field h_type char 10 n "house type: bungalow;""test quotes"" etc"

field lot_no num 10 i "lot number"

fc 1130, 1139

table lots free

field lot_no num 10 i u n "lot number"

field address_no num 6,0 i n

field street char 40 n "street name"

fc 1100

udb-feature

feat 1 1002 2 0 l xy 0 0 0 1 0

coor 1805 1120 1805 1143

coor 2018 1143 2018 1204 2508 1204

text "Elm Street"

attr Elm suburban 2 "asphalt"

feat 2 1004 2 0 l xy 0 0 0 1 0

coor 2508 1204 2508 820

text "Oak Street"

attr Oak arterial 4 "concrete"

feat 3 1400 5 2 l xy

coor 2508 903 2508 933

feat 4 1400 5 2 l xy

coor 2508 933 2568 933

feat 5 1400 5 2 l xy

coor 2568 933 2568 903

feat 6 1400 5 2 l xy

coor 2508 903 2568 903

feat 7 1400 5 2 l xy

coor 2508 873 2508 903

feat 8 1400 5 2 l xy

coor 2568 903 2568 873

feat 9 1400 5 2 l xy

coor 2508 873 2568 873

feat 20 1100 5 2 p xy

coor 2520 920

attr 10875, 104 Oak

feat 21 1133 5 0 l xy

coor 2530 920

attr 2-story 10875

feat 22 1100 5 2 p xy

coor 2520 890

attr 10874, 106 Oak

feat 23 1133 5 0 l xy

coor 2530 890

attr bungalow 10874

udb-polygon

poly 3 20 r e

poly 4 20 r e

poly 6 20 l e

poly 5 20 r e

poly 6 22 r e

poly 8 22 r e

poly 9 22 l e

poly 7 22 r e

udb-indirect

table road_types free

field r_type char 12 i u n "road type"

field maint char 2 "maintenance class"

field resp_code char 3 n "responsibility code"

attr highway m3 A-4

attr aterial m6 B-3

attr secondary n2 B-1

attr suburban s4 B-8

udb-indirect

table house_types free

field h_type char 10 i u n "house types"

field tax_code char 4 n "taxation code"

attr bungalow 10-5

attr 2-story 12-2

attr split 11-5

udb-end
 

Excel / Mapinfo Internal Format

The map files that are used with Excel for mapping can be imported and displayed.

Excel files are actually Mapinfo geographic files.

The format is not published so there may be problems with some files.

The geographic data comes as 4 files: .DAT, .ID, .TAB and .MAP. The extensions must be upper case (on LINUX).

Some datasets in Mapinfo internal format are available on the Web and are available for purchase from various vendors. We would reccomend using shape format if you have a choice as it is a published format.

Sample map data comes with Excel. On Office 97 it is in directory c:\Program Files\Common Files\Microsoft Shared\Datamap\Data. The sample attribute data is in the spreadsheet Mapstats.xls, which can be output in wk1 format for importing into OzGIS. See the section on spreadsheet data. There are several sample geographic files e.g. Europe.TAB, Europe.MAP, Europe.ID, Europe.DAT.
 

DXF format

Digitised map data can be entered into OzGIS in the AutoCAD Drawing Interchange and File format as lines, points and polygons.

The format is described in the AutoCAD manuals.

If the data are to be used for choropleth mapping (with attribute data) the entities must have been digitised with handles to give the entities names. The hexadecimal handle values will become the zone (or point) names that will also have to be used in the attribute files. You can rename the entities with a combine file by using the data reparation process, but the the easiest method is to edit the names with a word-processor. The names are treated as text. The handles are given in type 5 groups.

The entities are processed as follows:

LINEs are stored as line segments, and can only be used for line overlays as there is no left & right zone names to enable polygons to be built.

POINTs are stored as points. Any handle will be used as the name.

POLYLINE & VERTEXes give a series of points that are either lines for line overlays, or polygons if a bit flag values defines it as closed. If a handle value is given it becomes the name and attribute values can be linked to it (polygons).

TEXT entities are stored as points with the text group used as the name or for assigning attribute values (first 10 characters).
 

Digital Chart of the World

The Digital Chart of the World is a 1.7 GB digital geographic database that is available on CD-ROM. Like most US government data it is public domain, price about US$200!

More than 200 different types of attributes present worldwide are logically organized into 17 thematic layers. Since each thematic layer may contain information in the form of points, lines, and/or polygons, there are up to 27 possible coverages present. In addition to the attribute information most layers contain one or more levels of annotation. Most of the annotation contains place name information for cities, mountains, lakes, or other geographic features. Other types of annotation supplement attribute coding or contain data quality information. The original text size and location information are retained, thus allowing the production of publication quality maps. The major thematic layers in the DCW database include international boundaries, hydrography, elevation, populated places, roads, railroads, utility lines, airports, cultural landmarks, physiography, supplemental data, and data quality.

The Digital Chart of the World was input from 1:1,000,000 Operational Navigation Charts and 1:2,000,000 Joint Navigation Charts. It includes 17 layers, aeronautical info, data quality info, drainage, supplemental drainage, hypsography, hypsography supplemental, land cover, ocean features, physiography, political/ocean, populated places, railroads, transportation structure, utilities, and vegetation.

The data comes on 4 CD-ROMs and includes a BROWSE database for superficial views of the whole world, and 4 detailed databases.

The detailed databases are split into 5 degree square tiles.

Ponts, lines and text data can be imported as DCW files. Lines can be built into polygons with some restrictions.

A CD-ROM drive does not have to be on-line; files can be copied from another PC.

Refer to the complete chapter on DCW processing.
 

IDRISI Vector Format

Vector overlay files from the IDRISI raster GIS system can be entered. The files have a simple format of the form ident,number vertices

X,Y

. .

. .

X,Y

Where a 0,0 record indicates end of data

Points, lines or polygons can be entered.

Only records with one vertice will be processed for points, with more than one vertice for lines, and more than two vertices for polygons.

Three sample files are supplied for deaths during the 1854 London Cholera outbreak. These are STREET.VEC, DEATH.VEC and PUMP.VEC. See the associated *.DVC documentation files for details.

From NCGIA, Santa Barbara. Digitized in 1992 by Rusty Dodson from the map included in the book by John Snow: "Snow on Cholera...", London: Oxford University Press, 1936.

A trivial two line file could be:

1 2

16.7380009 18.6959991

17.6599998 18.7119999

36 3

11.3450403 4.9679508

11.0809002 4.4880772

11.6251144 3.5709989

0 0

ATLAS Export Format

Digitised boundary data can often be purchased in a format supported by the Atlas PC mapping system. The files are Ascii, and records are of the form:

"name",n,x1,y1,...........Xn,Yn

where

n=1 => a point

n=2 => a circle

n>2 => a polygon

n<0 => a line

These data can be entered via the OzGIS system with some restrictions:

An example file AFRICA.DAT may be included with your system:

"Morocco",141

13.92683,60.72203

13.92685,60.67901

13.99129,60.48547

14.1201,60.33495

14.24891,60.18444 A POLYGON

14.3777,60.07695

14.48501,60.05548

14.61376,60.07703

14.72104,60.09858

14.80687,60.14163

.

.

"Tunisia",113 A ZONE with 2 polygons

24.03397,61.15581

. . polygon 1

. .

24.03397,61.15581

25.49409,58.66141

. . polygon 2

. .

25.49409,58.66141

24.03397,61.15581 < - first point repeated after every polygon

.

.

"Mbabane",1

41.41317,7.313157

"Maseru",1

38.45704,4.957369 POINTS

"Pretoria",1

39.15494,8.036585

.

.

.

"euro3",-41

33.15051,61.9

33.10709,61.72918

33.14988,61.68601 A LINE

33.21407,61.62125

33.34267,61.55629

.

.

.

Atlas seems to handle multiple polygons within a zone by simply putting them all together in the record following the name i.e. if the first vertex is found to be equal to another in the following list, then that is the end of that polygon and the next vertex is the start of the next polygon etc. For some strange reason the first point of the region is repeated after each of the polygons.

Atlas does not support topologically structured polygons, so ensure that internal polygons are given after the containing polygons so they are not overwritten on the screen. Also, internal polygons that are to have the background colour should have names "OUTSIDE".

Apparently there are two possibilities for regions with multiple polygons: The polygons can be kept together, which results in the format which you see in the africa-files (see below). This is the default! The other possibility is to split the the region into separate polygons. This results in an export format where each polygon starts with the boundary name, number of vertices and then the vertices. (The easiest way to do this in ATLAS is to SELECT ALL, and then BOUNDARY, SPLIT, ISLANDS.)

The following is supposed to be from the ATLAS EXPORT/IMPORT MANUAL:

ISLANDS AND LAKES

The Island/Lake Rule

If you return to the first coordinate pair in the description of a region, you have closed the main polygon. The line to the next coordinate pair will not be drawn, but will instead signal the start of an island or lake. The last coordinate pair in the island or lake must be the same as the first one; this must also be followed by the first coordinate pair of the main polygon - this line again will not be drawn. This rule may be applied as many times in succession as necessary, one time for each island or lake. Curves created with Atlas*Draw can also have islands, but ASCII boundary files do not support this.

General Region Structure With Island/Lake

The format for a region containing an island and/or lake is:

"Pname","Sname",numxy

x1,y1

..

xn,yn

x1,y1

xx1,yy1,

..

xx1,yy1

x1,y1

The second xx1,yy1 pair closes the island or lake and is immediately followed by an x1,y1 pair, which closes back to the main polygon. Additional islands or lakes can follow, as long as each closes on itself and then closes back to the main polygon. The illustrations below show examples of a region with an island, and of a region with a lake containing an embedded region. The region with an island is listed as:

"Region w/Island",11

1,1 first coordinate pair

1,0

0,0

0,1

1,1 end of main polygon

2,1 start of island

3,1

3,0

2,0

2,1 end of island

1,1 end of main polygon

An entry for a region with a lake containing an embedded region:

"Region w/lake",11

0,3 first coordinate pair

3,3

3,0

0,0

0,3 end of main polygon

1,2 start of lake

1,1

2,1

2,2

1,2 end of lake

0,3 end of main polygon

"Embedded Region", 5

1,2

2,2

2,1

1,1

1,2

According to the documentation, regions with multiple polygons can name them all with a record of the form e.g. "poly1","poly2","poly3",num

The data we have seen does not seem to do this, but just gives one name.
 

MapInfo Data Interchange Format

Many data suppliers can provide geographic data in a format suitable for use with the MapInfo mapping system.

This format is partially supported, primarily for Census boundaries. The main restriction is that the more contrived spatial types are not supported.

The data is supplied usually as two files. The MapInfo Interchange File (MIF) contains the coordinates. The other file, the MID file, contains data, of which the only part of interest is the names of the spatial objects. Hence the MID file has to be given if you want to display attribute data, such as Census data, according to the names. Optionally the MID file need not be given, in which case the lines, points and polygons can only be used as overlays.

The MIF file starts with a header of the form:

Version 2

Delimiter ","

CoordSys Earth Projection 1, 0

Columns 2

Name Char(40)

ID Integer

Data

The only parts of the header used are:

"Delimiter" defines the seperator used in the MID file, default <tab>

"Columns" gives the number of values in the MID file for each object

"Data" indicates the end of the header and start of the coordinates etc

The data part of the file describes several types of objects. Only real geographic types are processed:

POINT and CENTER describe points (sites)

LINE and PLINE describe line segments

REGION describes zones (polygons)

Entries such as PEN are ignored.

A typical Census boundary file will have region entries with coordinates that will be output as polygons and centre's output as points. The polygons and the points will both have the same names from the MID file, so Census data can be mapped as either zones or sites, and the polygons and points can also be used for overlays e.g. to put names on the polygons.

For example, the data part of a MID file could look like:

Region 1

41

147.30982 -42.851953

147.309298 -42.851559

147.309174 -42.851233

147.309033 -42.851096

147.308207 -42.851211

. .

. .

. .

. .

. .

. .

147.312079 -42.850697

147.310575 -42.851964

147.30982 -42.851953

Pen (1,2,12582912)

Brush (2,16777215,16777215)

Center 147.308418 -42.848512

Region 1

13

147.286268 -42.838088

147.282985 -42.841294

147.283788 -42.842113

147.285434 -42.843622

147.286394 -42.844522

147.28709 -42.845175

147.289192 -42.847147

147.290486 -42.84662

. .

. .

. .

. .

The MID file provides the names of the objects as "columns". You will have to provide the number of the column that is the names (usually 1)

If a polygon is inside another it should have the name "OUTSIDE" so it will be displayed with the background colour.

A MID file with the name in column 1 looks like:

Canberra,637

Burra Creek,639

Phred,640

London,641

Wagga Wagga,642

1230807,644

.

.

ESRI Shapefile

Geographic data are available from many suppliers in the shapefile format. This was developed to support the ESRI ArcView system and is a documented format.

The data come as several files, the ones of interest being the basic geographic data as shape files, usually named with extension .SHP, and feature files in DBASE format, usually named with extensions .DBF.

Within OzGIS the data are imported by giving the .SHP files as data files and the .DBF files as parameter files.

For example you may have files WORLD.SHP and WORLD.DBF which you enter as data and parameter files respectively.

You can enter just the SHP file if all you need to do is draw the files. The DBF parameter files are usually required as they give the names of the geographic features, feature codes or left and right zone names for building polygons.

Some restrictions apply:

Only 16 characters are used for names within OzGIS, so be careful if you want to map associated attribute data using longer names.

Feature codes are numeric in OzGIS so you may have to edit the files to change text to numbers.

If you dont have DBASE you can look at the DBASE files in Excel, and do any necessary editing of values there.

Spatial Data Transfer Standard

Geograpfdgfdgdfgdmat.

The ddfgdgdffgdfg.

NAMES FILE FORMAT

Introduction

Names files give lists of zones, lines or sites which are to be used to restrict certain kinds of processing in OzGIS.

The file would usually be prepared with a text editor, possibly operating on a file output from OzGIS.

Comment Record:

80 byte comment describing the data

Name Records (one per zone or line or site)

16 byte name (
 

Sample names file DEMONAME.DAT

DEMONAMES.DAT - NAMES FILE

ZONE 1

ZONE 2

ZONE 4
 
 

COMBINE FILE FORMAT

Format

Combine files define new map zones in terms of zones in a base map, or site catchments in terms of percentages of base zones.

Comment record:

80 byte comment describing the file

Header record:

10 integer number of items defined

Sets of records follow for the items:

Item definition record:

16 byte name (ascending order)

10 integer number of zones

Zone records:

16 byte zone name (ascending order)

10 real proportion of zone in area (0 to 1.0)
 

Sample combine file DEMOCOMB.DAT

This file defines three territories AREA1, AREA2, AREA3 in terms of base zones A, B, ......

3 AREAS

3TEST AREAS

AREA1 1

H 1.0

AREA2 3

N 1.0

O 1.0

R 1.0

AREA3 5

A 1.0

B 1.0

C 1.0

D 1.0

E 1.0
 

DEVICE FILE FORMAT

Introduction

Device files describe the characteristics of graphics display devices and set colours etc.

Standard files are usually held on the system for all devices available. Users would not usually define their own.

OzGIS was designed to operate as a highly interactive colour mapping system where speed of display was obtained by the use of an advanced raster display system. The software can operate on most graphics devices, but there could be loss of speed and capabilities depending on the characteristics of the devices being used.

OzGIS is based on graphics packages with the functionality of the GKS graphic standard. These graphic packages provide graphic primitives such as lines, text, and filled polygons. An important feature of GKS is that it is device independent so the package allows OzGIS to produce maps on a large range of devices.

Every device available for use with OzGIS has at least one file associated with it.

All devices within OzGIS have the same characteristics so e.g. a map previewed on a display device can be output directly to a hard-copy device. The files ensure that a device with limited capabilities can simulate the required capabilities in the best way.

The device files also set GKS primitive attributes such as colours and zone fill types. A colour display system has several files available that provide standard sets of colours for maps.

The easiest way to generate device data files is to edit standard ones.

The device files require colours to be specified in blue,green,red. One way to decide on these values is to look at the definitions in the colour names data file \ozgis\x11-bgr.dat.

When outputting to a printer under WINDOWS you will find that you need a device file with a white background. Also, some printer drivers only show text that is black or white. The background is always assumed to be just the paper i.e. it is not coloured.

Format

Comment record:

80 byte Device description

Size record:

10 real Extent of device surface

Note: defines units used for all sizes in data i.e. divide by this

10 real width of device in device units (now set from OZGIS.INI)

10 real max address height of device (now set from OZGIS.INI)

Type record:

10 integer GKS workstation number

10 integer Display type, 1 = raster display, pixel addressed

2 = continuous coordinates

10 integer Fill type, 1 = solid colour

2 = pattern

3 = device hatching

4 = OzGIS hatching for OzMAP etc

5 = colour simulation for 4 pen plotter

10 integer Locator device number, 0 = none, 1 = default

2 = crosshairs

Advanced Raster Record (now set fromOZGIS.INI)

10 integer number of bit planes (1-24)

10 integer length of LUT (1-4096)

10 integer number of pixels across screen (256-4096)

10 integer number of lines on screen (256-4096)

10 integer run-length encoding/decoding, 0 = not available

Colour definition record:

10 integer number of colours defined (162)

Colour table records:

10 real blue value (0.0 - 1.0) for colour table

10 real green

10 real red

The rest of the data records set internal tables for GKS primitive

attributes. Most records reference the colour table; the index has range 1

to length of table.

Area Fill records:

10 integer colour index

10 integer fill or style index

Several fill records are required, in following order:

background. NOTE also the menu / messages/ everything colour

zone missing data

excluded zones

diagram background

line or site quantisation legend and diagram

8 polygon underlay records

Text records:

10 integer colour index

10 integer font number (1-9) as defined in OZGIS.INI

10 integer text precision 0=STRING, 1=CHAR, 2=STROKE

10 real height of character space (pixels)

10 real width of character space (pixels)

Fonts are available for use on the screen, but are more usually used for output

on plotters.

The text records are:

4 records to define the text available for name overlays at sites or typed in text.

The text is usually defined in increasing size order.

Legend text record: This is fixed size text used for generation of all the legends. The size is very important as it governs the overall size of the legend e.g. the zone legend boxes are 3 times the text height in height, 2 times the text width in width.

Attribute description text record: This is normally large text. The interactive system has to be able to clear it off for each attribute so it should be fixed size hardware text in that case. When two variates are displayed the two descriptions are separated by a 'VS' or 'AND' generated using the legend text.

Line records:

10 integer colour index

10 integer GKS type (1-4)

1 = solid, 2 = dashed, 3 = dotted, 4 = dash dot

The actual records are as follows:

4 records for lines to be used for line overlays.

4 records for lines to be used for quantised lines (line-type has no meaning here as types are assigned according to quantisation).

A record to define zone boundaries line.

A record to define the line used to draw axes on diagrams (should be solid).

A record to define the line used to draw statistical values on diagrams.

Marker records:

10 integer colour index

10 marker ident (number in marker font see OZGIS.INI

10 real marker height (and width)

The records are as follows:

4 records for markers to be used as overlays at sites.

4 records for markers used for sites with quantised attribute data (marker size has no meaning, is set for class).

1 record for site marker background (currently not used)

1 record for scatter diagram (GKS marker no 1)

Colour Sequence records (170 records):

10 integer colour index

10 integer style index

These records give sequences of colours for colouring zones after quantisation.

There are two types of sequence:

The class fill is found by sampling out of the sequence for the number of classes, e.g. for bivariate

2 classes 1 7

3 classes 1 4 7

4 classes 1 3 5 7

Similarly, the single variate 121 value array allows exact sampling for number of classes 2-7; a best choice is made for 8,9 or 10 classes. In the special case of pseudo-continuous colour maps the whole 121 values are used.
 

USA Census data

Overview

The best source of data is www.census.gov

The US Census Bureau supplies data on CD-ROM. There are two types supported:

1. the population and housing Census data (STF1A files), one State per CD-ROM

2. the digitised map data (TIGER format) supplied as one County per CD-ROM

The data entry process provides the facilities to input these data, BUT...

THE FILES MUST BE NAMED IN THE CORRECT WAY as described later.

The CD-ROM files can be very large, but the internal OzGIS files are much smaller. Hence the usual procedure will be to read the raw data files directly off CD-ROM. Processing can take some time.

The basic facility provided in the OzGIS system is to map tract/BNA or block group level data on a County basis. Census data can be extracted into one attribute file for one or more Counties. Census boundaries can be extracted into separate files for each county. Multiple county maps are generated by mapping the single attribute file with multiple geographic files.

Data for map overlays (e.g. roads) can also be extracted from TIGER data.

These data can be displayed without Census data.

Other data could be extracted from the CD-ROMs (e.g. blocks, places) and will be supported if there is demand. The capacity of the OzGIS system can be exceeded by these data..

The capacity should be sufficient to produce tract/BNA maps with overlays for single counties in all cases.

Generally the procedure for producing tract/BNA maps is to enter the TIGER data for the county of interest and all the STF1A files for the same county by selecting the appropriate options from the data entry menus.

Usually a new DOS directory will be set up for each map area. It must be on the same disk as the \OZGIS directory.

Census data is often not exactly what is required, PREPARE DATA FOR DISPLAY

will probably be used to produce derived attributes. Common processing is to

amalgamate age ranges and to normalise by dividing by total population.

The boundary line segments will probably be thinned to reduce

their size and speed up display by using the PREPARE DATA FOR DISPLAY option.

The BUILD TOPOLOGY option has to be used to form the polygons from the

TIGER lines data.

Finally the data are mapped with SIMPLE CENSUS-TYPE mapping of INTERACTIVE

DISPLAY AND ANALYSIS options.

The most important sections in this appendix are:

Processing STF1A data and

OzGIS Processing of TIGER data

These sections follow, with an example and further more general information

after that.

Documentation

Extensive documentation is available from the Census Bureau and on the

CD-ROMs.

Some of that documentation is reproduced here.

OzGIS Processing of TIGER data

You enter TIGER data into OzGIS with the data entry process.

Select IMPORT GEOGRAPHIC FILES from the top menu and then

IMPORT A TIGER FORMAT GEOGRAPHIC FILE

The next menu is:

TRACTS / BNA

BLOCK GROUPS

BLOCKS

ZIP CODES (IF PRESENT)

VOTING DISTRICTS

SELECT LANDMARKS BY FEATURE CODES

SELECT LINES BY FEATURE CODES

SELECT POINTS BY FEATURE CODES

You will probably use options TRACTS / BNA and BLOCK GROUPS to extract

boundaries for mapping with STF1A data. The build process has to be used

to build the polygons.

The option SELECT LINES BY FEATURE CODES will also be used often to extract

line overlay data such as roads.

The Feature codes are described later in this appendix.

It seems that each state is on at least one CD-ROM (some states like California

are on two or more, but most are either on one by themselves or share

a disk with one or two small states). The structure of the CD-ROM appears

to be: general documentation and full state FIPS listing files at

the top (GRF_N_xx, where xx is the state's FIPS code); a subdirectory

for each state named by its FIPS code (e.g. Indiana's subdirectory is 18); in

each state's subdir are subdirectories for each county, again by FIPS codes

(e.g. Allen County, Indiana is 003) using 3 digits; in each of these reside the

(finally!) Tiger files of the form TGRXXYYY.ZZn, where XX is the STATE code and

YYY is the county code and n is the record format code.

You usually read data directly off CD-ROM by giving the full file name.

The files will probably already be named correctly on CD-ROM, where they usually

to have extensions of the form ".ZZn". e.g. e:/36/121/tgr36121.f41. Every release of TIGER data seems to use different extensions.

You give the name of any one of the files and that name is used as a

template for the rest of the files.

There are two forms of file name:

Firstly, as files are often on CD-ROM with file names of the form, for

example boondocks.f41, boondocks.f42, boondocks.f43 etc, the data entry

process will look for sets of files with names of the form ????.??n

If no files are present of this form it will look for a second form, where

the file names must contain the string "TGRn" where n is 1,2,3 or 7. This

ensures that related files are named as a set.

Only the files of the required types are required:

Extracting Census boundaries usually requires types 1 and 2, but in some

cases the zone names (e.g. voting districts or 1980 regions) require that

the record type 3 file is also processed.

Extracting lines by feature code requires types 1 and 2.

Extracting points by feature codes requires type 1.

Extracting landmark features by feature code requires type 7.

Address extraction by feature code requires types 1 and 2. Type 6 records

are not processed.

Processing STF1A data

US Census data STF1A files can be entered into the system with the entry

process by choosing IMPORT ATTRIBUTE FILES from the menu and then

one of:

IMPORT USA CENSUS STF 1A FILES FOR TRACT/BNA

IMPORT USA CENSUS STF 1A FILES FOR BLOCK GROUPS

The data files must be present with names of the form *1An* where n is in

the range 0 to 9. The supplied files on CD-ROM will probably have extensions

DBF and file names in the correct form. Data files on hard disk are usually

given the extension .DAT

Example file names are e:/xyz/stf1a0dc.dbf, stf1a0in.dat, wash1a3.dat

You do not need to give the file extension if it is the default .DAT

All files present will be processed, so anywhere between 1 and 10 files

will be read. It takes a long time to read all the data, but it will be

usual to load it all in once.

You give the name of any one of the files and that name is used as a

template for the rest of the file names.

If you only want to process one or two files you will have to copy them to hard

disk. It will be usual to input files directly from CD-ROM as they can be very

big. The internal files are much smaller as only a small part of the data is

required.

THE FIRST STF1A FILE (number zero) MUST ALWAYS BE PRESENT as it contains the

level codes necessary to avoid multiple records being extracted.

A parameter file must be given. These are described in the next section.

You can use the supplied parameter file by giving the name as STF1A.PRM, as

described in the following section.

You can also set up your own parameter file, probably by modifying the example

provided.

Attributes (table variables) that are not on the parameter file will not be

processed, so a subset can be extracted by including just the appropriate

entries in the file.

You give a list of numbers for the counties you want to process e.g.

001, 005,...

If all the values for an attribute are zero nothing is written to the output

file for that attribute.

A log file is output to OZGIS.OUT which lists the attributes output and the

position on the file. The positions are of value when generating new

attributes as arithmetic expressions and for selecting attributes for display.

The STF1A parameter file

A parameter file must be used to define the description, units and number of

decimal places for each variable (field).

A sample parameter file is provided: \OZGIS\STF1A.PRM

This file was generated by editing the STF1A data dictionary, and there is no

guarantee that it is correct. (We would be pleased to accept a better version).

The format is fixed, so ensure any file has data in the correct columns if you

modify the file. The first line of the file is a comment, then there is one

line for each Census table variable that is to be processed in the following

format:

8 characters table name

2 characters filler

30 characters variable description

2 characters filler

10 characters units description

2 characters filler

1 digit number of decimal places (0 or 2)

The example parameter file is as follows:

Sample STF1A parameter file

P0010001 TOTAL PERSONS PERSONS 0

P0020001 TOTAL FAMILIES FAMILIES 0

P0030001 TOTAL HOUSEHOLDS HOUSEHOLDS 0

P0040001 PERSONS INSIDE URBANIZED AREA PERSONS 0

P0040002 PERSONS OUTSIDE URBANIZED AREA PERSONS 0

.

.

.

.

.

Example

You should have looked at the early chapters on entering data and displaying

Census-type maps before you look at this example.

Suppose you want to produce a map of 1990 Census data for three counties in

Texas for tract/BNA zones.

First you look up the county FIPS codes in the documentation:

48 Texas

.

.

48 047 Brooks County

.

.

48 117 Deaf Smith County

.

.

48 301 Loving County

So the codes are 047, 117 and 301.

Now set up a directory to work in on the SAME disk as the \OZGIS directory.

e.g.

CD \

MKDIR TEXAS

CD TEXAS

Now get the CD-ROM with the STF1A file for Texas and the TIGER CD-ROMs for

the three counties.

What you need to do is to prepare an attribute file with Census data for

the three counties and three geographic files, one for each county.

You will probably find it most profitable to work through this example

using your own CD-ROM files.

Step1: input the Census data

Mount the STF1A CD-ROM in the drive. Suppose the files are called

TEXAS1A0.DBF ......... TEXAS1A9.DBF.

Select IMPORT DATA FILES from the top menu.

A menu appears:

TUTORIALS & SYSTEM INFORMATION

IMPORT GEOGRAPHIC FILES

IMPORT ATTRIBUTE FILES

IMPORT A NAMES FILE

IMPORT A COMBINE FILE

IMPORT A DEVICE FILE

IMPORT A MARKER FILE

select the option to IMPORT ATTRIBUTE FILES

A new menu appears:

IMPORT A STANDARD FORMAT ATTRIBUTE FILE

IMPORT A SPREADSHEET WK1 FORMAT FILE

IMPORT A DATABASE (SIMPLE) FORMAT ATTRIBUTE FILE

IMPORT A LAMM FORMAT ATTRIBUTE FILE

IMPORT USA CENSUS STF 1A FILES FOR TRACT/BNA

IMPORT USA CENSUS STF 1A FILES FOR BLOCK GROUPS

IMPORT ATLAS DATA FILES

Obviously you now select:

IMPORT USA CENSUS STF 1A FILES FOR TRACT/BNA

Give the input data file as E:/xxx/TEXAS1A0.DBF (using the correct drive)

Give the output attribute file as TEXAS1 (no extension!!)

Give the parameter file as *STF1A

Give the numbers for the counties i.e. 047, 117 and 301.

All the files will be processed. Trace messages will say what is going on.

Exit from the program.

Either print the file OZGIS.OUT or copy it to a file. This is a list of

the census variables and their positions in the attribute file.

Some comments ....... the file name given (TEXAS1A0.DBF) is used as a template

to generate the other file names (TEXAS1A1.DBF etc) and all files in the set

on the CD-ROM are processed.

If the file name is not of the standard form you have to copy the files to

hard disk and rename them.

You can process just some of the files by copying them to hard disk (the first

file, number zero, must always be there). i.e. all the files present are

processed.

Step2: derive census variables (optional)

You now have an attribute file called TEXAS1 ready for mapping. However,

raw Census variables are often not exactly what you want.

Suppose you actually want to map teenagers in the age group 12 to 15 years old.

Also, if you are interested in the way the data are spatially distributed you

have to normalise the data to allow for differences in the total number of

people in the different tract/BNAs.

This can be done as follows:

First look at the file OZGIS.OUT from the data entry process to find the

variable numbers. Suppose it looks like:

1 TOTAL PERSONS

.

.

.

108 12 AND 13 YEARS

109 14 YEARS

110 15 YEARS

.

.

.

The new variable is the sum of the three age variables, divided by the total.

Now select PREPARE DATA FOR DISPLAY from the top menu.

The menu looks like:

PROCESS ATTRIBUTE FILES

PROCESS GEOGRAPHIC FILES

PROCESS NAMES FILES

OUTPUT EXTERNAL DATA FILES

Select PROCESS ATTRIBUTE FILES, which gives another menu:

FORM ATTRIBUTES WITH ARITHMETIC EXPRESSIONS

AMALGAMATE ATTRIBUTE DATA FOR AN COMBINE FILE

Select FORM ATTRIBUTES WITH ARITHMETIC EXPRESSIONS

Now you have to specify an input attribute file, which is here TEXAS1, and a

new output file, say TEXAS2

You can then define a series of arithmetic operations (type H for help)

So you give the arithmetic expression as:

(#108+#109+#110) / #1 * 100.0

You also have to give a description, say "12 TO 15 YEAR OLDS" and a

units description, say "%POP".

Type an expression "E" to exit.

Step 3: Enter the TIGER data

You will have a CD-ROM for each County. Put the first in the drive.

Suppose the files for Brooks County have names tgr48047.d41, tgr48047.f42 etc

Select IMPORT DATA FILES from the top menu.

select IMPORT GEOGRAPHIC FILES and then IMPORT A TIGER FORMAT GEOGRAPHIC FILE.

The TIGER menu is:

TRACTS / BNA

BLOCK GROUPS

BLOCKS

ZIP CODES (IF PRESENT)

VOTING DISTRICTS

SELECT LANDMARKS BY FEATURE CODES

SELECT LINES BY FEATURE CODES

SELECT POINTS BY FEATURE CODES

Obviously, you need to select TRACTS / BNA as that is what you extracted

Census data for.

As before, give the input data as the name of one of the CD-ROM files, say

D:/48/047/TGR48047.F42, and the new geographic file as say BROOKS1

If there are problems reading the files you may have to copy the ones required

to hard disk and rename them, as described in previous sections.

The file BROOKS1 contains the lines that form the boundaries of the tract/BNAs.

Suppose you also would like to display a lines overlay on your map of important

roads.

Looking at the section on feature codes you find that a range of 110 to 128

covers primary and secondary roads.

So, select SELECT LINES BY FEATURE CODES

Give the input data file as before, and the output geographic file as

say BROOKRD

Give the feature code range as found: 110 to 128

Repeat the process for the TIGER files for each of the counties so you

end up with a geographic file of boundaries for tract/BNAs for each county,

and line overlay files for the roads.

Step4: Simplify lines

Often you will want to thin the lines data i.e. throw away a lot of the points.

You do this for several reasons:

. The less the number of vertices the faster map display is.

. You often dont care if the map is particularly accurate, its the attribute

data you are interested in.

. Your screen is low resolution, there is no advantage in having many vertices

for each pixel on the monitor.

. When you form polygons from the lines the number of vertices in some

polygons may exceed system limits.

. Geographic files take less disk space after thinning.

Simplification is an option in the data preparation process which reads a

geographic file and outputs a new one where the line segments have less points.

So, select PREPARE DATA FOR DISPLAY from the top menu.

Select PROCESS GEOGRAPHIC FILES and then select SIMPLIFY (THIN) LINE SEGMENTS

Give the input file as BROOKS1 and the new output file as BROOKS2.

The resolution for thinning is given as the number of pixels. For example,

if you are displaying maps on a standard VGA at 640 X 480 you might give

the resolution as 450 pixels. If you are more interested in speed of

display than appearance give a value of 100.

Repeat for the other files.

Step5: Form polygons from lines

The geographic files of tract/BNAs contain the line segments that form the

boundaries of the Census regions.

You have to form the zone / polygon / line structure by joining the ends of

the lines to form polygons, finding which polygons form the zones and

working out which polygons are inside others.

Select BUILD ZONES FROM LINE SEGMENTS INTO NEW GEOGRAPHIC FILE

Give the input geographic file as BROOKS2

Give the output geographic file as BROOKS

The program will now build the polygons etc.

Repeat for the other tract/BNA boundary files (not the roads!)

If you type "DIR BROO*.GEO" you will find that you have the three geographic

files created during processing:

BROOKS.GEO

BROOKS1.GEO

BROOKS2.GEO

You only need the final one, so you can delete BROOKS1.GEO and BROOKS2.GEO

Step6: Display simple maps

You can start by displaying some simple maps with SIMPLE CENSUS-TYPE MAPPING.

The first menu appears:

1 TUTORIALS & SYSTEM INFORMATION

2 DISPLAY A NEW MAP

choose the option to "DISPLAY A NEW MAP".

give your attribute file name i.e. TEXAS1

and give your final geographic file name i.e. BROOKS

The data are now processed, the map is displayed, and the next menu appears.

You now have a default map with legend and distribution diagram. The legend

has the numbers of zones in each class on the left and the class value ranges

to the right of the coloured boxes.

If you use an option such as changing the displayed attribute you may have

Refer to the chapter at the front of the manual on using Census mapping if you

have not already looked at the example there.

Step7: Display complex maps

Lets display a map with the three counties tract/BNA geographic files, called

say BROOKS, DEAF and LOVING. The raw attribute file TEXAS1 will be used and

the three road overlay files BROOKSRD, DEAFRD and LOVINGRD will be used.

Type OZGIS to execute the main mapping program.

the first menu enables you to select the type of map or diagram that is

required:

DISPLAY ZONES FOR AN ATTRIBUTE FILE

DISPLAY LINES FOR AN ATTRIBUTE FILE

DISPLAY SITES FOR AN ATTRIBUTE FILE

DISPLAY BIVARIATE ZONES FOR TWO ATTRIBUTE FILES

DISPLAY ZONES & LINES FOR TWO ATTRIBUTE FILES

DISPLAY ZONES AND SITES FOR TWO ATTRIBUTE FILES

DISPLAY GEOGRAPHIC FILES (NO ATTRIBUTES)

DISPLAY ATTRIBUTE FILES (DIAGRAMS)

DISPLAY A SAVED-DISPLAY FILE

DISPLAY A PRESENTATION FILE

Select DISPLAY ZONES FOR AN ATTRIBUTE FILE for a straight forward

choropleth map.

Give the attribute file as TEXAS1 and give one of the geographic boundary

files, say BROOKS.

A map will be displayed that will be the same as that with the Census mapping

process. The difference is that you now have many more options for mapping.

The main mapping menu will now appear on the toolbar:

Attributes

Class

Features

Overlays

Regions

Analyse

Save

First we will add the other two tract/BNA files to the map. This requires

an understanding of map regions which are defined by both a geographic

window and the part of the screen it is to appear on.

select MAP REGIONS.

A menu then appears of the following form:

CHANGE THE DISPLAYED ITEMS IN THE MAP

CHANGE MAP REGION WINDOW (GEOGRAPHIC AREA)

ZOOM MAP REGION WINDOW ABOUT X-HAIR POINT

CHANGE MAP REGION VIEWPORT (SCREEN AREA)

DEFINE NEW REGION FOR QUANTISED ZONES

DISPLAY MORE QUANTISED ZONES ON A REGION

DELETE QUANTISED ZONES FROM REGION

What you do next depends on whether the counties are adjacent or not.

If counties are adjacent, add the files to the existing map region as

follows:

select ZOOM MAP REGION WINDOW ABOUT X-HAIR POINT, choose a location with

the cursor and mouse or arrows (select with left button or Enter). Give

a zoom factor, say 4.

You now have space for the other counties. Select DISPLAY MORE QUANTISED ZONES

ON A REGION and give the next boundary geographic file DEAF. Repeat for LOVING.

If the counties are not adjacent you probably want to display the files in

different parts of the screen in their own regions. Use the option

DEFINE NEW REGION FOR QUANTISED ZONES to do this.

You probably end up with a mess. Use CHANGE MAP REGION WINDOW (GEOGRAPHIC AREA)

and CHANGE MAP REGION VIEWPORT (SCREEN AREA) to clean up the map layout.

You often find that Census maps have very small polygons in the centres of

cities. You can add "blow-ups" of the CBDs by using DEFINE NEW REGION FOR

QUANTISED ZONES to add a geographic file a second time to the map and then

use CHANGE MAP REGION WINDOW (GEOGRAPHIC AREA) to display just the desired

area. (you can also use data preparation options to subset for complete polygons

Finally add the roads. Type ESC to go back to the main map menu and

select DEFINE GEOGRAPHIC OVERLAYS

A menu appears that offers options for several types of overlays:

OVERLAY LINE SEGMENTS FROM A GEOGRAPHIC FILE

OVERLAY MARKERS FOR SITES IN GEOGRAPHIC FILE

OVERLAY NAMES FOR SITES IN GEOGRAPHIC FILE

UNDERLAY POLYGONS FROM GEOGRAPHIC FILE

OVERLAY LINE SEGMENTS FOR FEATURE CODES

OVERLAY MARKERS FOR SITES FOR FEATURE CODES

OVERLAY NAMES FOR SITES FOR FEATURE CODES

UNDERLAY POLYGONS FOR FEATURE CODES

Use OVERLAY LINE SEGMENTS FROM A GEOGRAPHIC FILE to overlay the road geographic

files BROOKSRD, DEAFRD and LOVINGRD one at a time. If you have more than one

region you will have to give the region number - the number is defined by the

order the regions were defined. You could also use OVERLAY LINE SEGMENTS FOR

FEATURE CODES and give a feature code range to subset the lines further.

You can add the names of the tract/BNAs to the map by using OVERLAY NAMES FOR

SITES IN GEOGRAPHIC FILE and adding each of the boundary files.

Having spent all this time you dont want to lose the map, so save it with the

option SAVE DISPLAY FEATURES from the main map menu.

The other options are all described fully elsewhere in the manual.
 

OzGIS Census Zone Names

Federal Information Processing Standards (FIPS) codes are assigned

for a variety of geographic entities, including American Indian and

Alaska Native area, congressional district, county, county subdivision,

metropolitan area, place, and State. The structure, format, and meaning

of FIPS codes used in the census are shown in the 1990 census

Geographic Identification Code Scheme; in the data dictionary portion of

the technical documentation for summary tape files, CD-ROM's, and

microfiche.

The names assigned to Census polygons in OzGIS are generated from the

standard codes.

Tract / BNA name = 3digit county + 5 digit tract FIPS code

Block group name = 3digit county + 5 digit tract FIPS code + first block digit

If you want to input your own data try generating a template attribute data

file with the data preparation options.

These names are unique only within a state.

STF1A Census data

Summary Tape File 1 (STF 1) contains 100-percent data. Population items

include age, race, sex, marital status, Hispanic origin, household type,

and household relationship. Population items are cross tabulated by age,

race, Hispanic origin, or sex. Housing items include occupancy/vacancy

status, tenure, units in structure, contract rent, meals included in

rent, value, and number of rooms in housing unit. Housing data are cross

tabulated by race or Hispanic origin of householder or by tenure.

Selected aggregates and medians also are provided. Data are presented in

37 population tables (matrices) and 63 housing tables (matrices).

STF1A Geographic areas 




Blocks

Census blocks are small areas bounded on all sides by visible features such

as streets, roads, streams, and railroad tracks, and by invisible

boundaries such as city, town, township, and county limits, property lines,

and short, imaginary extensions of streets and roads.

Tabulation blocks, used in census data products, are in most cases the

same as collection blocks, used in the census enumeration. In some

cases, collection blocks have been "split" into two or more parts

required for data tabulations. Tabulation blocks do not cross the

boundaries of counties, county subdivisions, places, census tracts or

block numbering areas, American Indian and Alaska Native areas,

congressional districts, voting districts, urban or rural areas, or

urbanized areas. The 1990 census is the first for which the entire

United States and its possessions are block-numbered.

Blocks are numbered uniquely within each census tract or BNA. A block

is identified by a three-digit number, sometimes with a single

alphabetical suffix. Block numbers with suffixes generally represent

collection blocks that were "split" in order to identify separate

geographic entities that divide the original block. For example, when a

city limit runs through data collection block 101, the data for the

portion inside the city is tabulated in block 101A and the portion

outside, in block 101B. A block number with the suffix "Z"

represents a "crews-of-vessels" entity for which the Census

Bureau tabulates data, but that does not represent a true geographic

area; such a block is shown on census maps associated with an anchor

symbol and a census tract or block numbering area with a .99 suffix.

Block Groups

A geographic block group (BG) is a cluster of blocks having the same

first digit of their three-digit identifying numbers within a census

tract or block numbering area (BNA). For example, BG 3 within a census

tract or BNA includes all blocks numbered between 301 and 397. In most

cases, the numbering involves substantially fewer than 97 blocks.

Geographic BG's never cross census tract or BNA boundaries, but may

cross the boundaries of county subdivisions, places, American Indian

and Alaska Native areas, urbanized areas, voting districts, and

congressional districts. BG's generally contain between 250 and 550

housing units, with the ideal size being 400 housing units.

Block Numbering Area (BNA)

Block numbering areas (BNA's) are small statistical subdivisions of

a county for grouping and numbering blocks in nonmetropolitan counties

where local census statistical areas committees have not established

census tracts. State agencies and the Census Bureau delineated BNA's

for the 1990 census, using guidelines similar to those for the

delineation of census tracts. BNA's do not cross county boundaries.

BNA's are identified by a four-digit basic number and may have a

two-digit suffix; for example, 9901.07. The decimal point separating

the four-digit basic BNA number from the two-digit suffix is shown in

printed reports, in microfiche, and on census maps; in machine-readable

files, the decimal point is implied. Many BNA's do not have a suffix;

in such cases, the suffix field is left blank in all data products. BNA

numbers range from 9501 through 9989.99, and are unique within a county

(numbers in the range of 0001 through 9499.99 denote a census tract).

The suffix .99 identifies a BNA that was populated entirely by persons

aboard one or more civilian or military ships. A "crews-of-vessels" BNA

appears on census maps only as an anchor symbol with its BNA number (and

block numbers on maps showing block numbers); the BNA relates to the ships

associated with the onshore BNA's having the same four-digit basic number.

Suffixes in the range .80 through .98 usually identify BNA's that either

were revised or were created during the 1990 census data collection

activities. Some of these revisions produced BNA's that have extremely

small land area and ay have little or no population or housing. For data

analysis, such a BNA can be summarized with an adjacent BNA.

Census Tract

Census tracts are small, relatively permanent statistical subdivisions of a

county. Census tracts are delineated for all metropolitan areas (MA's) and

other densely populated counties by local census statistical areas

committees following Census Bureau guidelines (more than 3,000 census

tracts have been established in 221 counties outside MA's). Six States

(California, Connecticut, Delaware, Hawaii, New Jersey, and Rhode Island)

and the District of Columbia are covered entirely by census tracts. Census

tracts usually have between 2,500 and 8,000 persons and, when first

delineated, are designed to be homogeneous with respect to population

characteristics, economic status, and living conditions. Census tracts do

not cross county boundaries. The spatial size of census tracts varies

widely depending on the density of settlement. Census tract boundaries are

delineated with the intention of being maintained over a long time so that

statistical comparisons can be made from census to census. However,

physical changes in street patterns caused by highway construction, new

development, etc., may require occasional revisions; census tracts

occasionally are split due to large population growth, or combined as a

result of substantial population decline. Census tracts are referred to

as "tracts" in all 1990 data products.

Census tracts are identified by a four-digit basic number and may have

a two-digit suffix; for example, 6059.02. The decimal point separating

the four-digit basic tract number from the two-digit suffix is shown in

printed reports, in microfiche, and on census maps; in machine-readable

files, the decimal point is implied. Many census tracts do not have a

suffix; in such cases, the suffix field is left blank in all data

products. Leading zeros in a census tract number (for example, 002502)

are shown only on machine-readable files.

Census tract numbers range from 0001 through 9499.99 and are unique

within a county (numbers in the range of 9501 through 9989.99 denote a

block numbering area). The suffix .99 identifies a census tract that

was populated entirely by persons aboard one or more civilian or

military ships. A "crews-of-vessels" census tract appears on

census maps only as an anchor symbol with its census tract number (and

block numbers on maps showing block numbers). These census tracts

relate to the ships associated with the on-shore census tract having

the same four-digit basic number. Suffixes in the range .80 through .98

usually identify census tracts that either were revised or were created

during the 1990 census data collection activities. Some of these

revisions may have resulted in census tracts that have extremely small

land area and may have little or no population or housing. For data

analysis, such a census tract can be summarized with an adjacent census

tract.

County

The primary political divisions of most States are termed "counties." In

Louisiana, these divisions are known as "parishes." In Alaska, which has no

counties, the county equivalents are the organized "boroughs" and the

"census areas" that are delineated for statistical purposes by the State of

Alaska and the Census Bureau. In four States (Maryland, Missouri, Nevada,

and Virginia), there are one or more cities that are independent of any

county organization and thus constitute primary divisions of their States.

These cities are known as "independent cities" and are treated as

equivalent to counties for statistical purposes. That part of Yellowstone

National Park in Montana is treated as a county equivalent. The District of

Columbia has no primary divisions, and the entire area is considered

equivalent to a county for statistical purposes.

Each county and county equivalent is assigned a three-digit FIPS code

that is unique within State. These codes are assigned in alphabetical

order of county or county equivalent within State, except for the

independent cities, which follow the listing of counties.

Hierarchical Presentation

A hierarchical geographic presentation shows the geographic entities

in a superior/subordinate structure in census products. This structure

is derived from the legal, administrative, or areal relationships of

the entities. The hierarchical structure is depicted in report tables

by means of indentation, and is explained for machine-readable media in

the discussion of file structure in the geographic coverage portion of

the abstract in the technical documentation. An example of hierarchical

presentation is the "standard census geographic hierarchy": block, within

block group, within census tract or block numbering area, within place,

within county subdivision, within county, within State, within division,

within region, within the United States. Graphically, this is shown as:

Zip codes

ZIP Codes are administrative units established by the United States

Postal Service (USPS) for the distribution of mail. ZIP Codes serve

addresses for the most efficient delivery of mail, and therefore

generally do not respect political or census statistical area

boundaries. ZIP Codes usually do not have clearly identifiable

boundaries, often serve a continually changing area, are changed

periodically to meet postal requirements, and do not cover all the land

area of the United States. ZIP Codes are identified by five-digit codes

assigned by the USPS. The first three digits identify a major city or

sectional distribution center, and the last two digits generally

signify a specific post office's delivery area or point. For the 1990

census, ZIP Code data are tabulated for the five-digit codes in STF 3B.

The STF1A file 




File Segments

The file is segmented into 10 dBase III (.DBF) files, designated

STF1A0ss.DBF through STF1A9ss.DBF where ss is the two-character State

abbreviation. The STF1A0 segment contains the full 67 field identification

section. The identification field names are shown in the Data Dictionary

chapter of the technical documentation. Segments STF1A1 through STF1A9

each contain seven identification fields repeated from the STF1A0 segment.

They are shown below.

Identification Fields Common To All Segments

SUMLEV Summary Level

STATEFP State (FIPS)

CNTY County (FIPS)

COUSUBFP County Subdivision (FIPS)

PLACEFP Place (FIPS)

TRACTBNA Census Tract/Block Numbering Area

BLCKGR Block Group

LOGRECNU Logical Record Number

The segments are divided as shown below. Tables 12 and 13 go across

segments.

Data Tables In Each Segment

STF1A0 P1 - P10

STF1A1 P11 - P12(pt.2)

STF1A2 P12(pt. 3) - P12(pt. 5)

STF1A3 P12(pt. 6) - P12(pt. 8)

STF1A4 P12(pt. 9) - P13(pt. 1)

STF1A5 P13(pt. 2) - P19

STF1A6 P20 - P35

STF1A7 P36, H1 - H20

STF1A8 H21 - H40

STF1A9 H41 - H55

Parts of Table P12

(Each part contains 31 categories of age)

Part 1 White males

Part 2 White females

Part 3 Black males

Part 4 Black females

Part 5 American Indian, Eskimo or Aleut males

Part 6 American Indian, Eskimo or Aleut females

Part 7 Asian or Pacific Islander males

Part 8 Asian or Pacific Islander females

Part 9 Other race males

Part 10 Other race females

Parts of Table P13

(Each part contains 31 categories of age)

Part 1 Hispanic origin males

Part 2 Hispanic origin females

You can process all or some of the files.

Field Names In Numeric Data Tables

Fields in numeric data tables are named according to a convention which

identifies the tables and the sequence of the data item within the table.

The 310 data items in P12, for example, are identified as P0120001 through

P0120310. The one data item in table H23A is identified as H023A001.

Components Of The Field Name

Character 1 P or H

Character 2-4 Table number; right justified with

leading zeroes

Character 5 Sub-table letter; zero if not applicable

Character 6-8 Item number; right justified with

leading zeroes

TIGER US Census Digital Map Data

The 1990 Census TIGER/Line file provides digital data for all 1990 census

map features and boundaries, the associated 1990 census final tabulation

geographic area codes (such as 1990 census block numbers), and the codes

for the January 1, 1990 legal and statistical areas on both sides of each

line segment of every mapped feature. This version also contains the final

voting district codes and the 1990 census designated place codes.

The 1990 Census TIGER/Line files cover the entire United States, Puerto

Rico, the Virgin Islands of the United States, American Samoa, Guam, the

Northern Mariana Islands, Palau, the other Pacific entities that were part

of the Trust Territory of the United States for the 1980 census (the

Marshall Islands and the Federated States of Micronesia), and the Midway

Islands (to provide complete mapping within the boundaries of the State of

Hawaii).

TIGER files

The normal geographic coverage for a 1990 Census TIGER/Line file is a

county. The files can be combined to cover the whole Nation and its

possessions. Each 1990 Census TIGER/Line file consists of 12 record types

that collectively contain geographic information (attributes) such as

address ranges and ZIP codes for street segments (only in areas covered by

the 1980 GBF/DIME-Files), names and codes of feature types, codes for legal

and statistical entities, selected 1980 census geographic area codes,

latitude/longitude coordinates of linear and point features, landmark

features, area landmarks, and area and polygon boundaries. The 12 record

types are on the tape as 12 separate files.

The 1990 Census TIGER/Line file contains basic information for 1990 census

geographic area codes, basic map features and their names, and address

ranges in the form of 12 "Record Types." The record types are as follows:

1. Basic Data Records (Individual Feature Segment Records)

2. Shape Coordinate Points (Feature Shape Records)

3. Additional Decennial Census Geographic Area Codes

4. Index to Alternate Feature Names

5. Feature Name List

6. Additional Address Range and ZIP Code(2) Information

7. Landmark Features

8. Area Landmarks

A. Additional Polygon Geographic Area Codes

I. Area Boundaries

P. Polygon Location

R. Record Number Range

Each segment record contains appropriate decennial census and, when

appropriate, FIPS(1) geographic area codes, latitude/longitude coordinates

for all line segments and point features, the name of the feature

(including the relevant census feature class code identifying the segment

by category), and, for areas formerly covered by the GBF/DIME-Files, the

address ranges and the ZIP Code associated with those address ranges for

each side of street segments. For other areas, the TIGER/Line files do not

contain address ranges or ZIP Codes. The shape records provide coordinate

values that describe the shape of those feature segments that are not

straight.

Record types 1,2,3 and 7 are processed by OzGIS. The types used depend on

the options chosen:

Record Type 1: Basic Data Record

Record Type 1 provides a single record for each unique line segment in the

1990 Census TIGER/Line file. The end points of the line segments are

expressed in latitude/longitude coordinate values in degrees and decimal

fractions of a degree to six decimal places. This record also contains

address ranges and ZIP codes (in selected areas) and geographic area codes

for each side of the line segment. By convention, if one is standing at

the "from" coordinate position facing the "to" coordinate position,

data listed in the fields carrying a right qualifier would indeed be found

to the right of the line segment. Data users can collect the necessary

segments to construct polygons and features that intersect from the

information contained in this basic record.

Record Type 2: Shape Coordinate Points

Record Type 2 provides an additional series of latitude and longitude

coordinate values that describe the shape of each line segment that is not

straight for the associated Record Type 1. All coordinate values are

expressed in degrees and decimal fractions of a degree of latitude and

longitude. The decimals are carried to six places to permit the

representation of lines that are very close to one another. If the segment

in Record Type 1 is a straight line, there will not be a Record Type 2.

Record Type 3: Additional Decennial Census Geographic Area Codes

Record Type 3 includes the 1990 voting district codes provided to the

Census Bureau for the 1990 Census Redistricting Data Program. Record Type

3 also includes some 1980 census geographic area codes and 1990 census

geographic area codes not included on Record Type 1. The 1980 census block

numbers are available only for areas covered by the 1980 GBF/DIME-Files.

During the conversion of the 1980 GBF/DIME-Files to the TIGER data base

format, some 1980 census block numbers may have been deleted or changed.

Users are advised to check all 1980 census geographic area codes,

especially any 1980 block numbers, before using them in a planned

application. The Census Bureau has not verified any of the 1980 census

geographic area codes in these files. There will be discrepancies between

the geographic area boundaries and codes in these files and the 1980 census

maps, which are the basis for the 1980 census tabulations.

The TIGER/Line files may contain 1980 block numbers for portions of the

country where the Census Bureau did not tabulate 1980 census data by block

or block group. These situations occur because these portions of the TIGER

file originated from the 1980 GBF/DIME-Files that extended beyond the 1980

block-numbered area. Data users concerned about the validity of 1980 block

numbers are advised to discard all 1980 block numbers that do not

correspond to block numbers in the 1980 MARF or 1980 STF files.

Record Type 6: Additional Address Range and ZIP Code Data

Record Type 6 provides additional address range information for a street

segment when the information cannot be presented as a single address range

(e.g., the house/building numbers are not uniformly arranged to form an

address range). Additional ZIP Codes, if any, also appear in Record Type 6

for corresponding address ranges. Record Type 6 appears only for those

counties that have address ranges and ZIP Code information in the TIGER

data base. There is no assurance that the address ranges provided on

Record Type 6 will be "shorter" than those appearing on Record Type 1.

Data users must use Record Type 6 to obtain the complete picture of the

potential address ranges along a segment.

Record Type 7: Landmark Features

Record Type 7 contains the area and point landmarks in the Census Bureau's

TIGER data base. During the extraction of this data, we assigned a

temporary Landmark Identification Number that we use to link the landmark

attributes to the polygons that comprise the landmark. If there is no

landmark in a county file, there will be no Record Type 7 or Record Type 8

for that county file.

TIGER Geographic Area Definitions

United States - The 50 States and the District of Columbia.

States and Statistically Equivalent Areas - The 50 States; in addition, we

treat the District of Columbia, Puerto Rico, and each of the outlying

areas-American Samoa, Guam, the Northern Mariana Islands, Palau, and the

Virgin Islands of the United States-as statistical equivalents to States

for presentation. We also have TIGER/Line files for the Marshall Islands,

the Federated States of Micronesia, and the Midway Islands.

Counties, Parishes, Statistically Equivalent Areas - The first-order

divisions of each State, the District of Columbia, Puerto Rico, and the

outlying areas: counties for 48 States; parishes for Louisiana; boroughs

and census areas for Alaska; independent cities in Maryland, Missouri,

Nevada, and Virginia; Yellowstone National Park in Montana, "District of

Columbia" for the District of Columbia, municipios in Puerto Rico; other

entities in the outlying areas.

Minor Civil Divisions (MCDs) - Legally defined subcounty areas such as

towns and townships. For the 1990 census, these are found in 28 States,

Puerto Rico, and the outlying areas.

Sub-MCDs - Legally defined subdivisions of a minor civil division;

specifically, subbarrios in Puerto Rico, and municipal districts in the

Federated States of Micronesia.

Incorporated Places - Legal units incorporated as a city, town (excluding

the New England States, New York, and Wisconsin), borough (excluding Alaska

and New York), or village.

American Indian Reservations - American Indian areas with boundaries

established by treaty, statute, and/or executive or court order.

Alaska Native Regional Corporations (ANRCs) - Corporate entities

established by the Alaska Native Claims Settlement Act (P.L. 92-203) to

carry out the business and non-profit operations established by and for

Native Alaskans under the Act. Twelve ANRCs have specific boundaries and

cover the State of Alaska except for the Annette Islands Reserve.

Statistical Areas

Alaska Native Village Statistical Areas (ANVSAs) - 1990 census statistical

areas that delineate the settled area of each Alaska Native village (ANV).

Officials of Alaska Native Regional Corporations (ANRCs) and other

appropriate State officials delineated the ANVSAs for the Census Bureau for

the sole purpose of presenting census data.

Tribal Designated Statistical Areas (TDSAs) - Geographic areas delineated

for 1990 census data tabulation purposes by tribal officials of Federally

and State-recognized tribes outside of Oklahoma that do not have a legally

defined reservation.

Tribal Jurisdiction Statistical Areas (TJSAs) - Geographic areas delineated

for 1990 census data tabulation purposes by tribal officials in Oklahoma

for Federally recognized tribes that do not have a legally defined

reservation.

Census County Divisions (CCDs) - Areas delineated by the Census Bureau in

cooperation with State and local officials in States where MCDs are not

adequate for reporting subcounty statistics.

Unorganized Territories (UTs) - Areas delineated by the Census Bureau for

those portions of a State with MCDs where MCDs do not exist or are not

adequate for reporting subcounty statistics.

Census Designated Places (CDPs) - Densely settled population centers

without legally defined corporate limits or corporate powers, defined in

cooperation with State officials and local data users.

Census Tracts - Small, locally delineated statistical areas within selected

counties, generally having stable boundaries and, when first established by

local committees, designed to have relatively homogeneous demographic

characteristics.

Block Numbering Areas (BNAs) - Areas delineated by State governments or the

Census Bureau for the purpose of grouping and numbering blocks in counties

without census tracts.

Census Blocks - Small, usually compact areas, usually bounded by streets

and other prominent physical features as well as boundaries of legal areas

for which the Census Bureau tabulates data. Blocks do not cross county,

census tract, or BNA boundaries.

Voting Districts (VTDs) - For the 1990 census, the term "voting district"

replaces the 1980 census term "election precinct." A voting district is

any of a variety of areas (for example, election districts, precincts,

legislative districts, wards) defined by State and local governments for

purposes of elections. The 1990 voting district codes that appear in the

1990 census version of the TIGER/Line files were supplied by the State

under the 1990 Census Redistricting Data Program. The boundaries of the

voting districts recorded in the TIGER/Line files may represent pseudo-

voting districts; the States were required to have voting districts follow

1990 census block boundaries, and therefore they may have had to relocate

the boundaries of actual voting districts to a nearby feature used as a

block boundary. States had the option of participating in the program on a

county-by-county basis. Voting districts do not appear in all TIGER/Line

files.

TIGER feature codes

Data can be extracted from the TIGER files and subset for display by

feature codes.

Feature codes are derived from the Census Feature Class Codes (CFCC)

by changing the leading alphabetic character by its position in the

alphabet.

This is a series of codes that provides more detailed information on the

classification of the line segment, such as class of road, class of stream,

and so forth.

A list of these codes follows.

CFCC CLASSIFICATION A = ROAD FEATURES

100 Road, Classification Unknown or Not Elsewhere Classified

101 Road, undivided

102 Road, undivided, in tunnel

103 Road, undivided, underpassing

104 Road, undivided, rail line in center

105 Road, divided

106 Road, divided, in tunnel

107 Road, divided, underpassing

108 Road, divided, rail line in center

110 Primary road, interstate highway and limited access road

111 Primary road, interstate highway and limited access road, undivided

112 Primary road, interstate highway and limited access road,

undivided, in tunnel

113 Primary road, interstate highway and limited access road,

undivided, underpassing

114 Primary road, interstate highway and limited access road,

undivided, rail line in center

115 Primary road, interstate highway and limited access road, divided

116 Primary road, interstate highway and limited access road, divided,

in tunnel

117 Primary road, interstate highway and limited access road, divided,

underpassing

118 Primary road, interstate highway and limited access road, divided,

rail line in center

120 Secondary road, U.S. highway not classified 110, and state roads

121 Secondary road, U.S. highway not classified 110, and state roads,

undivided

122 Secondary road, U.S. highway not classified 110, and state roads,

undivided, in tunnel

123 Secondary road, U.S. highway not classified 110, and state roads,

undivided, underpassing

124 Secondary road, U.S. highway not classified 110, and state roads,

undivided, rail line in center

125 Secondary road, U.S. highway not classified 110, and state roads,

divided

126 Secondary road, U.S. highway not classified 110, and state roads,

divided, in tunnel

127 Secondary road, U.S. highway not classified 110, and state roads,

divided, underpassing

128 Secondary road, U.S. highway not classified 110, and state roads,

divided, rail line in center

130 Connecting road, county roads, and roads not classified as 110 or

120

131 Connecting road, county roads, and roads not classified as 110 or

120, undivided

132 Connecting road, county roads, and roads not classified as 110 or

120, undivided, in tunnel

133 Connecting road, county roads, and roads not classified as 110 or

120, undivided, underpassing

134 Connecting road, county roads, and roads not classified as 110 or

120, undivided, rail line in center

135 Connecting road, county roads, and roads not classified as 110 or

120, divided

136 Connecting road, county roads, and roads not classified as 110 or

120, divided, in tunnel

137 Connecting road, county roads, and roads not classified as 110 or

120, divided, underpassing

138 Connecting road, county roads, and roads not classified as 110 or

120, divided, rail line in center

140 Neighborhood roads, city streets and unimproved roads

141 Neighborhood roads, city streets and unimproved roads, undivided

142 Neighborhood roads, city streets and unimproved roads, undivided,

in tunnel

143 Neighborhood roads, city streets and unimproved roads, undivided,

underpassing

144 Neighborhood roads, city streets and unimproved roads, undivided,

rail line in center

145 Neighborhood roads, city streets and unimproved roads, divided

146 Neighborhood roads, city streets and unimproved roads, divided, in

tunnel

147 Neighborhood roads, city streets and unimproved roads, divided,

underpassing

148 Neighborhood roads, city streets and unimproved roads, divided,

rail line in center

150 Jeep trail, passable only by four-wheel drive (4WD) vehicle

151 Jeep trail, passable only by four-wheel drive (4WD) vehicle,

undivided

152 Jeep trail, passable only by four-wheel drive (4WD) vehicle,

undivided, in tunnel

153 Jeep trail, passable only by four-wheel drive (4WD) vehicle,

undivided, underpassing

160 Special Road Feature

161 Cul-de-sac

162 Traffic circle

163 Cloverleaf or interchange

164 Service drive

165 Ferry crossing

170 Other Thoroughfare

171 Walkway

172 Stairway

173 Alley

NOTE: In the portion of the TIGER/Line file prepared from the GBF/DIME-

Files, the roads are classified as Class 4 roads with a few exceptions.

The interstate highways that were identified by name as such in the

GBF/DIME-File, are classified as Class 1 roads. Also, in the GBF/DIME-File

coverage areas, users may not find many roads with alternate names; if an

alternate name is provided, it usually represents another local name and

not a Route Number.

CFCC CLASSIFICATION B = RAIL FEATURES

200 Railroad, Classification Unknown or Not Elsewhere Classified

201 Railroad track

202 Railroad track, in tunnel

203 Railroad track, underpassing

210 Railroad Main Track

211 Railroad main track

212 Railroad main track, in tunnel

213 Railroad main track, underpassing

220 Railroad Spur Track

221 Railroad spur track

222 Railroad spur track, in tunnel

223 Railroad spur track, underpassing

230 Railroad Yard

231 Railroad yard

232 Railroad yard, in tunnel

233 Railroad yard, underpassing

240 Railroad Ferry Crossing

250 Other Rail Feature

251 Carline

252 Cog railroad, incline railway, or logging tram

CFCC CLASSIFICATION C = PIPELINES, POWER TRANSMISSION LINES, AND

MISCELLANEOUS TRANSPORTATION FEATURES

300 Special Transportation Feature, Classification Unknown or Not

Elsewhere Classified

310 Pipeline

320 Power Transmission Line

330 Other Special Transportation Feature

331 Aerial tramway, monorail, or ski lift

CFCC CLASSIFICATION D = LANDMARK FEATURES

400 Landmark Feature, Classification Unknown or Not Elsewhere

Classified

410 Military installation

420 Multihousehold and transient quarters

421 Apartment building or complex

422 Rooming or boarding house

423 Trailer court or mobile home park

424 Marina

425 Crew of vessel

426 Housing facility for workers

427 Hotel, motel, resort, spa, YMCA, or YWCA

428 Campground

429 Shelter or mission

430 Custodial facility

431 Hospital

432 Halfway house

433 Nursing home, retirement home, or home for the aged

434 County home or poor farm

435 Orphanage

436 Jail or detention center

437 Federal penitentiary, state prison, or prison farm

440 Educational or religious institution

441 Sorority or fraternity

442 Convent or monastery

443 Educational institution

444 Religious institution

450 Transportation terminal

451 Airport or airfield

452 Train station

453 Bus terminal

454 Marine terminal

455 Seaplane anchorage

460 Employment center

461 Shopping center or major retail center

462 Industrial building or industrial park

463 Office building or office park

464 Amusement center

465 Government center

466 Other employment center

470 Tower

471 Lookout tower

480 Open space

481 Golf course

482 Cemetery

483 National park or forest

484 Other federal land

485 State or local park or forest

490 Special purpose landmark

491 Post office box ZIP code

CFCC CLASSIFICATION E = OTHER PHYSICAL FEATURES

500 Physical Feature, Classification Unknown or Not Elsewhere

Classified

510 Fence line

520 Topographic feature

521 Ridge line

522 Mountain peak

CFCC CLASSIFICATION F = NONVISIBLE BOUNDARIES

600 Nonvisible Boundary, Classification unknown or not Elsewhere

Classified

610 Nonvisible Political Boundary

611 Offset corporate boundary

612 Corporate Corridor

613 Nonvisible interpolated boundary, polygon definition line for

hydrological areas

620 Feature Extension, Not Otherwise Classified

621 Automated extension

622 Irregular block extension

623 Closure extension

624 Nonvisible separation line

625 Nonvisible corporate corridor centerline

630 Point-to-Point Line

640 Property Line

650 ZIP Code Boundary

660 Map Edge

670 Statistical Boundary

671 1980 Statistical Boundary

672 1990 Block Boundary

673 1990 Statistical Boundary

674 1990 Statistical Boundary, Tabulation Areas Only

CFCC CLASSIFICATION H = HYDROGRAPHIC FEATURES

800 Water Feature, Classification Unknown or Not Elsewhere Classified

801 Shoreline of perennial water feature

802 Shoreline of intermittent water feature

810 Stream

811 Perennial stream

812 Intermittent stream or wash

813 Braided stream

820 Canal, Ditch, or Aqueduct

821 Perennial canal, ditch, or aqueduct

822 Intermittent canal, ditch, or aqueduct

830 Lake or pond

831 Perennial lake or pond

832 Intermittent lake or pond

840 Reservoir

841 Perennial reservoir

842 Intermittent reservoir

850 Bay, Estuary, Gulf, Sound, Sea, or Ocean

851 Bay, estuary, gulf, or sound

853 Sea or ocean

860 Gravel Pit or Quarry Filled With Water

870 Nonvisible Water Area Definition Boundary

871 USGS closure line

872 Census computed center line

873 Census international water boundary, 10-mile limit, area

measurement line

874 Census water boundary, inland or coastal or Great Lakes

875 3-mile limit water boundary

880 Special Water Feature

881 Glacier
 

GLOSSARY OF TERMS

The purpose of this Appendix is to provide definitions for a number of terms used within this Guide. Most of these terms are commonly used words or phrases which have taken on a more precise technical meaning in one of the areas spanned by the OzGIS system. Technical terms have been borrowed from the jargon of statistics, data processing, computer software and hardware, cartography, and graphic arts. Because of the diversity of these disciplines, it is unlikely that a potential OzGIS user will have developed a level of expertise in each. This glossary should provide most of the information necessary for communicating the basic concepts of OzGIS.

Area - 1) A measurement of the size of a geographical region whose shape is displayed on the OzGIS monitor. 2) An arbitrary portion of the face of the monitor.

Attribute - A general term for the variable associated with a set of geographic zones, lines or sites to be processed by OzGIS. Attributes may be variates, statistics or simply data collected for each item. Note that the modes of display for an attribute are usually referred to as "single variate" or "bi-variate". See also Variate and Statistic.

Background - The informationless area displayed on the monitor around a map and its associated components. Usually given a user selected, neutral colour such as black or white.

Bit - A unit of information representing the value (either 1 or 0) of a single binary digit.

Bivariate - A display of the relative distribution of two different sets of statistics on the same map. It must be noted that no relationship between the two statistics is implied by the display. For example, if the distribution of little old ladies is displayed simultaneously with the distribution of cricket players, the result is not a display of the distribution of little old ladies who play cricket. See also Variate.

Boundary - A set of lines displayed on the monitor to represent the edges of polygons defined to the system. Often the same as zone edges.

Byte - A group of eight bits. See also Bit.

Catchment - The region of influence around a site e.g. suburbs around a shopping centre where most of the customers live.

Character - A single symbolic pattern which may be displayed on either the monitor or terminal. It may be alphabetic, numeric, or punctuational, as the normal symbols encountered on a typical typewriter keyboard, or a special symbol generated for display as an entity, such as a square root symbol.

Choropleth Map - A map portraying the values of an attribute averaged over data collection units (or zones) and represented by a symbol covering the entire unit. A map displayed by OzGIS represents the zones by a uniform colour.

Class - A convenient subdivision of the total range of values of a particular statistical variate. Classes are usually chosen to make computations or analyses less labourious, or to make the results of such analyses more obvious or meaningful. For example, the range of a set of values might be divided into ten equal classes in order to highlight items in the top ten percent. See also Variate, Class Boundary, Class Interval and Class Number.

Class Boundary - The special values of variates which determine the upper and lower limits of the range of a class. See also Class.

Class Interval - The range of variate values between the upper and lower limits of the class. See also Class.

Class Number - A cardinal number assigned to each class into which a particular statistical range has been divided. Conventionally, the class whose members have the lowest magnitude is assigned number 1, with class numbers increasing uniformly as the magnitude of class values increases. See also Class.

Colour - One of the combinations of blue, green, and red which may be specified for display on the monitor. The total number of colours available depends on the display system.

Colour Space - The range of colours which may be specified for display on the colour monitor. Since the colours are specified as values of blue, green, and red, it is convenient to think of the colour space as a cube located on a standard three dimensional coordinate system. Black is placed at the origin, with each of the x, y and z axes representing blue, green, and red, respectively. The range of possible values is 0.0 to 1.0 on each axis of the cube.

Continuous Colour - A method of representating statistical values associated with map zones by graduating zone colours to correspond with changes in statistical value. From a user defined, or default, sequence of colours, OzGIS generates the intermediate colours to provide a 12 colour graduated path through the colour space. The statistic to be represented is quantized into 12 equal value classes, and the classes are assigned colours from the generated colour sequence. This allows small changes in statistical value to be represented by subtle changes in colour, while large changes in value may be visually observed as significant colour differences.

Controller - A general term applied to a piece of intermediate equipment in the data path between the electrical signals of a processor and their physical realization in a peripheral device. Within OzGIS, the term will most often be used for the Color Display Controller. It will be used to a lesser extent to describe interface controllers for the various disc and tape drives.

Coordinate - One of a pair of numbers which designates the location of a geographic point with respect to another known point. Geographic files for entry into the system under OzGIS must have their points specified in appropriately scaled and formatted coordinates. The coordinates specified by the user are converted by OzGIS for display on the monitor. On the monitor screen, the origin is in the lower left hand corner of the viewing area. The coordinates of a point on the monitor screen are specified by their distance right and up from the origin

Crosshair Cursor - A pair of lines at right angles to each other which is displayed on the monitor to designate the location of a certain point of interest. Under most circumstances, the location of the crosshair cursor may be controlled by movements of the mouse. See also Box Cursor, and Joystick.

Data - Numerical values associated with certain physical phenomena, such as 128 cm long, 14 years old, or 43 kangaroos. As a generality, OzGIS was not designed to handle data, but rather the statistics derived from data, such as average length, medium age, or number of kangaroos per hectare. See also Statistics.

Decile - One of the nine data values which divide the range of a variate into ten equal sized classes. See also Quantile and Percentile.

Default - A set of parameters automatically selected by OzGIS in the absence of any stated preference by the user. The actual default parameters may be defined by the user in the users default file. For example, OzGIS may initially display a map by arbitrarily selecting zone colours from a palette of possible shades which the user selected previously. After this default colouring, the user may wish to change some particular zone colour to improve the appearance of the display.

Disc - An electronic device for storing digital data on a rotating plate coated with magnetic material. See also Controller.

Display - As a verb, the act of presenting information on the monitor or terminal for the purpose of visually communicating that information to the user. This includes all the procedures necessary to correctly present the information in a format suitable for both the equipment and the viewer. Example: "A map is displayed on the monitor, while a menu is displayed on the terminal". As a noun, the presentation which is visually perceived when a user looks at the screen of the monitor or terminal; the total information content on the screen. Examples: "The terminal display indicates the options possible now"; "This map display is too red". See also Monitor and Terminal.

Display Elements - The components or items of a display on the OzGIS monitor; for example, legend, title, image map, boundaries, image symbols, histograms.

Distribution - The manner in which a number of samples of data are spread across the range of possible values. May be a subjective statement, such as: "These data appear to have an even distribution". More often, some quantifiable measure will be given such as: "These data have a normal distribution with a mean of 40 and standard deviation of 3". Sometimes, distribution information will be presented in graphical form, such as a histogram or scatter diagram.

Equal Value Quantization - A method of dividing the range of values of a statistical variate into a number of classes where the magnitude of the range of each class is the same. See also Class.

Excluded Zone - A zone displayed on the map and coloured with a special shade indicating that it has not been used for quantization or has been omitted from the area of interest.

File - A number of data items grouped together and considered as a unit for convenience of storage and retrieval by a computer. Within OzGIS, such files are stored as distinct entities on disk. Files are identified by media designation, name, and type. The OzGIS user normally supplies only the file name, but the storage media may also be specified. The file type is supplied by the system. The same name may be used for files of different types, but within a particular type, no two files may have the same name.

Frequency - A statistical term referring to the number of members of a population falling into a specified class. See also Class.

Geographic Data - Digitized map data which are referenced to a geographic (or spatial) coordinate system, usually a map projection.

Graphics - Data which can be displayed on the monitor in terms of lines points and text, as opposed to colouring and filling regions of the screen. Used to refer to geographic and symbol data.

Histogram - A type of bar graph in which vertical rectangles are erected on the horizontal axis with the height of each bar representing the frequency, and the width representing the corresponding class interval,

for each of the classes of a particular variate. OzGIS can display

such statistical information on the monitor. See also Scatter Diagram,

and Class.

Information - The subjective knowledge which may be associated with an objective set of data. The ages and locations of children are data; the distribution of school age children is statistic; where the schools should be built is information. See also Data and Statistics.

Interval - The numerical distance between the upper and lower limits of a class.

Joystick - An electro-mechanical device which converts the positions of a small lever into electrical voltages. The voltages are further converted into digital signals which are used by the PDP11 to position various cursor patterns on the monitor screen. See also Box Cursor, and Crosshair Cursor.

Legend - A display on the monitor which indicates the correspondence between the statistical values and their associated colours or symbols as defined for a particular map. The legend usually occupies approximately the rightmost one fifth of the viewing area of the monitor and has two general forms, single variate and bivariate. One type of single variate legend consists of a column of coloured rectangles beside which are numbers indicating the corresponding class boundaries for those colours. The other is a rectangular column with colours gradually changing from top to bottom, and an upper and lower number indicating the range across which the "Continous Colour" varies. The bivariate legend consists of a 45 degree parallelogram divided left to right and up and down into coloured smaller parallelograms. A set of numbers along the left side indicates the class boundaries of the primary variate, while similar numbers across the upper side indicate the secondary variate class boundaries.

Line - This term has three special meanings within OzGIS in addition to its normal English usage. (1) Any set of contiguous segments comprising the section of a zone boundary which has one zone on its right and a second zone on its left as part of a map. (2) Any contiguous set of segments as part of a graphics display. (3) A set of alpha-numeric characters meant to be displayed as one row on either the monitor or the terminal.

Location - The position of a datum point, or pixel, on the monitor screen. This is given by its x and y coordinates, with the origin in the lower left hand corner. The range of values depends on the display system. Lookup Table (LUT) - A table in the display system which can modify the value in memory for display purposes.

Map - Geographic data which can be displayed on the monitor by colouring and filling regions of the screen or as lines or symbols.

Map Projection - Refers to the coordinate system used for processing the display of a map.

Markers - Special characters or symbols which may be displayed on the monitor to identify locations of points. For example, aircraft symbols to indicate the location of airports. Different sized markers

are used to show the classification of site attribute data.

Mean - The arithmetic average of a set of data values.

Memory - A portion of the OzGIS hardware used for the storage of data by the altering of the electrical state of the appropriate circuitry.

Menu - An itemized list of alternative actions which might be selected within OzGIS. Menus are displayed on the terminal. The terminal keyboard is used to enter selections from the options listed on the menu. The sequence of menu items which is selected controls the "flow" of the OzGIS program through its various tasks.

Monitor - The electronic equipment, resembling a colour television receiver, on which maps and graphics are displayed.

Nested Means - A quantization method in which classes are generated by dividing each variate range into two classes about the mean for that range. For example, the central class limit is set at the overall mean, then the upper and lower classes are each divided at the means of the two parts, giving four classes. This process may be repeated, giving eight classes.

Operating System - Computer software provided to facilitate usage of the various computer resources available within the OzGIS system.

Overlay - As a noun, overlay refers to graphic data written on top of the existing display. This is displayed on the monitor as though placed between the previous display and the viewer. Overlays generally are entered in the refresh memory in single bit planes. As a verb, overlay refers to the act of adding graphics data to a display by putting it "on top of" the previous display.

Palette - An array of coloured rectangles which is displayed on the monitor at certain stages of OzGIS. The palette shows a range of colours which are available for selection by the user..

Parameter - A general term referring to a physical characteristic which may be measured or quantified in some way, even though the precise value of that measurement may be unknown in specific instances. For example, age is a parameter of human beings.

Percentile - One of the set of 99 values which divide the range of a statistic into 100 equal sized classes.

Peripherals - Items of auxillary equipment added to a computer to enhance its performance. These include such items as disc drives, tape drives, and printers.

Pixel - The smallest, individually controllable, element (or cell) displayed as dots of colour on the monitor's screen. The monitor area is made up of lines of pixels. For each pixel, there is a corresponding location in the refresh memory for storing the data value associated with that pixel. This location is the smallest datum area which can be individually controlled by the software. See also Image and Location.

Point - A geographic feature which, for display purposes, may be described by only indicating its location as an x and y coordinate.

Polygon - A geographic area described by the line segments forming its boundary and the zone name which forms its surface. One or more polygons may be combined to form a zone.

Primary Variate - The set of statistical values characterized by a common name which is displayed on any given single variate map. Two such sets of values are displayed on a bivariate map. The primary variate is named at the top of the title, and its colour values are indicated in the rows of the legend. See also Variate.

Projection - The representation of a physical shape on the screen of the monitor according to a fixed mathematical coordinate system. Normally, a projection in OzGIS terms will refer to a method for presenting maps of geographic areas. See also Map Projection.

Quantile - Any of the specific values which divide the range of a statistic into equal sized classes. Some values have other special terms, i.e., if the range is divided into four classes, the boundary values are called quartiles. See also Percentile.

Quantify - To assign a number or quantity to an otherwise unnumbered entity. In particular, to assign a class number to a statistical value or zone name.

Quantization - The process of assigning class numbers to zones according to the value of the statistic for that zone. Viewed the other way, quantization is the process of putting zones into classes. Quartile - One of the three data values which divide the range of a variate into four equal sized classes. See also Quantile and Percentile. Raster - a term applied to image data. In particular data handled on a line basis.

Refresh Memory - The portion of the hardware (within the display controller) which holds the digital data necessary to continuously regenerate the colour monitor display. The cathode ray tube (CRT) of the monitor produces its display by electrically stimulating various phosphorus based compounds deposited on its face. The colours thus produced fade rapidly with time and must be continually "refreshed". The data necessary to perform this refresh correctly is stored in the refresh memory.

Region - A designated portion of a map displayed on the monitor. A region consists of one or more zones or parts of zones defined in some way (e.g. a circular region centered at a point on the map). The concept of a region is important when the displayed map consists of several geographic areas. In this context, a region consists of a window (geographic area) and its displayed viewport on the screen (screen area). See also Area.

Save - To store on disc (or magnetic tape) all the pertinent data regarding a map displayed on the monitor. The maps which are "saved" can later be fully regenerated with all details preserved.

Scatter Diagram - A two dimensional plot of points whose x and y coordinates are the values of the individual variates associated with those points. Scatter diagrams are displayed on the monitor in conjunction with bivariate maps. In this instance, each map zone is assigned a point on the diagram. The y-coordinate of the point corresponds to the value of the primary variate for that zone as displayed on the map. The x-coordinate of the point has a similar relationship to the secondary variate. In addition, the point will be coloured the same as its associated map zone. Scatter diagrams provide a visual method of assessing the correlation between the two variates displayed on the map.

Secondary Variate - The second set of statistical values which are displayed (along with a primary variate) on the map. The secondary variate is named at the bottom of the title. See also Primary Variate.

Segment - A set of connected straight lines defined to OzGIS by specifying the coordinates of their starting, intermediate, and end points, along with the names of the two zones on either side of the lines. Consequently, segments must represent a portion, or all, of the boundary between two zones. See also Line and Boundary.

Site - A geographic location that has associated attribute data. A site is defined by a name and fixed location e.g. a site could be a city or a retail store.

Standard Deviation - A statistical measure of the dispersion amongst a set of measured values. The standard deviation is mathematically equivalent to the positive square root of the variance of the sample on which the statistic is based.

Statistics - A general term referring to: 1) The branch of mathematics involved with performing certain analytical calculations regarding various relationships among sets of numerical data, and 2) The numerical results of such calculations. The height of an individual is data; the average height of a group is a statistic.

Status - The present condition of the software and hardware system, especially as to its progress toward the completion of the tasks at hand. The status messages are displayed as a response to typing interpretation of various abbreviated messages displayed on the terminal. The status messages are displayed as a response to typing an "S" command.

Terminal - An item of hardware comprising a keyboard for entering commands to the processor, and some means for the processor to return alpha-numeric messages to the user. The standard OzGIS terminal is the Digital Equipment Corporation VT100. This contains the necessary keyboard, and a cathode ray tube for displaying processor generated messages. Some OzGIS installations may also have a printer terminal for providing a permanent copy of the messages on paper.

Territory - a zone which has been formed by amalgamating bas zones e.g. sales territories formed from postcodes.

Text - Combinations of characters which may be specified by typing at the terminal. Lines of text may be displayed on either the terminal or the monitor in various fonts. See also Character, and Line.

Time Lapse Maps - A formatted set of maps concerning a geographic area and certain statistics associated with it as they have been collected over time. Time lapse files are used to display the time related changes in the statistical data by rapid and periodic changes in map colours corresponding to the statistics. For example, variations in population density, as recorded by the 1971, 1976, and 1981 census data, could be shown by changing the colours of the displayed map at one second intervals corresponding to the 3 sets of data.

User - The person who is interactively controlling the OzGIS system at the terminal.

Value - The number associated with a particular statistical item, as opposed to the colour associated with that item. For example, the zone might be coloured red to indicate four to ten beer drinkers per pub in that zone. The actual value of the statistic might be 9.4 beer drinkers per pub.

Variate - A measurable quantity which may take on any of the values within a given range, and which has associated with it a specified probability function describing the manner in which the permissible values are likely to occur. See also Bivariate, Primary Variate, and Secondary Variate.

Viewport - The rectangular area of the colour monitor face selected for displaying a specified item.

Window - The rectangular portion of a geographic map which is selected for display on the colour monitor.

Zone - A geographic area which is to be considered as a spatial unit. A zone is defined in terms of one or more polygons which form it. Statistically, a zone is defined in terms of a single value for each variate in question. This relationship of one variate value per defined geographic zone allows zones to be completely and uniformly coloured in a map display. See also Polygon and Variate.

Zone Name - An alphanumeric designation attached to the various computerized data associated with a zone. The zone name facilitates for the processor the task of relating various data items to the proper

zones.

SYSTEM LIMITS

The OzGIS system has a standard set of limits to various maximum counts. These correspond to array sizes.

30000 max no displayed zones+sites+lines

30000 max no values in attribute file (zones,sites,lines)

100 max no map regions

100 max no quantised zone geog files

100 max no quantised site geog files

100 max no quantised line geog files

100 max no line overlays

100 max no polygon underlays

100 max no marker overlays

100 max no name overlays

100 max no text strings displayed

500 max no polygons in a zone

5000 max no segments in a polygon

100 max no segments in a line

5000 max no vertices in a segment

20000 max no points in a fast display polygon

1000 max no zones per item in a combine file

256 max length of display system LUT (number colours)

50000 max no vertices in foreign segments data file

30000 max no zones that can be built from line segments

10000 max no vertices in object for spatial operations

5000 max no items in a text attribute file

15000 max no zones in a catchment

max no points in a catchment polygon

max no contours in a site catchment

120000 max no sitesXpoints for location allocation

50000 max no quantised zone, line or site handles

REFERENCES

O'CALLAGHAN, J.F., SIMONS, L. and PALMER, J.A.B. (1980). A prototype system for interactive colour mapping. Proc. URPIS-8 (k. Davies (ed.)), Surfers Paradise, pp. 9.1-9.5.

SIMONS, L., O'CALLAGHAN, J.F. and PAINE, T. (1982). COLOURMAP - an interactive colour mapping workstation. Proc. DECUS (Digital Equipment Computer Users Society), Melbourne, Vol. 10, pp.1501-1504.

O'CALLAGHAN J.F., and SIMONS, L.W.J. (1983) COLOURMAP: An Interactive Colour Mapping System. Proc. First Australasian Conference on Computer

Graphics, Sydney.

O'CALLAGHAN J.F., and SIMONS, L.W.J. (1984). Map Display Techniques for Interactive Colour Mapping.

Henzell, O'Callaghan. A Sequential Line Simplification Algorithm based on Equivalent Height. CSIRONET Technical Report, May 1980

Robertson, O'Callaghan. The Generation of Colour Sequences for Univariate and Bivariate Mapping. IEEE Computer Graphics and Applications, February 1986.

Gerald Evenden. Cartographic Projection Procedures for the UNIX Environment - A User's Manual. USGS open-file report 90-284.

TIGER/Line Census Files, 1990 Technical Documentation / prepared by the Bureau of the Census. Washington: The Bureau, 1991.

Atef A Elassal. General Cartographic Transformation Package (GCTP), Version ii NOAA Technical Report NOS 124 CGS 9

J Sibert, 'Continuous-colour Choropleth Maps', Geo-Processing, (1980) 207-216.

'The Harvard Library of Computer Graphics Mapping Collection', Harvard University.

E Giamottic and P Puliafits, 'An Interactive Spatial Information System: A Tool for Regional Planning'; Proc IFIP 79.

J Dalton et al, 'Interactive Colour Map Displays of Domestic Information', Proc SIGGRAPH 79, Computer Graphics, Vol 13 No 2 ACM/SiGGRAPH.

A Robinson et al, 'Elements of Cartography', Wiley 1978.

D Des Jardins, 'Multi-Level Statistical Maps in Graphic Communication', Proc NCGA, Anaheim 1982.

"ACORD: AUTOMATIC COUNTOURING OF RAW DATA, Computers & Geosciences, vol. 8, no. 1, p. 97-101, 1982", by D.F. Watson.

L Cooper, 'Location allocation problems', Operatons Research 11, p 331-343 1963.

Goodchild and Massam, 'The transportation-location problem', Operations Research 20, 1969.

Tornqvist et al, Multiple Location Analysis, 1971.

EXAMPLES

Introduction

Most of the examples are also available as saved map files. They require the standard example files supplied with OzGIS. All the files must be in the C:\OZDATA directory.

The examples can be displayed by using the File->Open menu item.

Demonstration

You should start by looking at the OzGIS demonstration which consists of a series of saved maps.

The demonstration is available on the net as the file OZDEMO.ZIP

Simple Zones Map - SIMPLE.OZA

The first example is a choropleth map of Australia, which is an example of a very common type of map to display attributedata like Census data, sales data, or government statistics.

Within WINDOWS run OzGIS.

Choose Map from the toolbar, and then DISPLAY ZONES FOR AN ATTRIBUTE FILE from the pulldown menu.

give the attribute file name as FEA (or select fea.att)

give the geographic file name as FEA (or select fea.geo)

You will have a default map with legend and distribution diagram. The legend has the numbers of zones in each class on the left and the class value ranges to the right of the coloured boxes.
 

Example of data entry

You will often have a file of attribute data (such as population Census data) and a file of digitised boundary data for mapping (e.g. TIGER): We will look at data for Australia. There are two data files:

OZ-G.DAT are the digitised boundary data, (Australian Statistical Divisions)

OZ-A.DAT are the attribute data

Execute the OzGIS program.

Choose the IMPORT pulldown menu.

A menu will appear like:

IMPORT GEOGRAPHIC FILES

IMPORT ATTRIBUTE FILES

IMPORT A NAMES FILE

IMPORT A COMBINE FILE

IMPORT A DEVICE FILE

IMPORT A MARKER FILE

First enter the digitised boundary data:

Select the option to IMPORT GEOGRAPHIC FILES

The popup menu appears:

IMPORT A STANDARD FORMAT GEOGRAPHIC FILE

IMPORT NEW FORMAT SAS GEOGRAPHIC FILE

IMPORT OLD FORMAT SAS GEOGRAPHIC FILE

IMPORT A DLG-3 OPTIONAL FORMAT GEOGRAPHIC FILE

IMPORT A GINA FORMAT GEOGRAPHIC FILE

IMPORT A TIGER FORMAT GEOGRAPHIC FILE

IMPORT A DIME FORMAT GEOGRAPHIC FILE

IMPORT A DXF FORMAT GEOGRAPHIC FILE

IMPORT AUSLIG SEGMENTS FORMAT CENSUS BOUNDARY FILE

This enables geographic data to be read in in a variety of "standard" formats.

The test data is in the OzGIS standard format so choose

IMPORT STANDARD FORMAT GEOGRAPHIC FILE

A file open dialog now appears for you to specify a file name. Go to the \OZDATA directory.. You type in

what you want and then type enter:

give the input data file as OZ-G or select OZ-G.DAT

give the output geographic file as OZ

The data file will be processed, and a standard geographic file created.

The trace message at the top of the screen describes what is going on.

Now enter the attribute data:

select the option to IMPORT ATTRIBUTE FILES from the Import pulldown mwnu.

A new menu appears:

IMPORT A STANDARD FORMAT ATTRIBUTE FILE

IMPORT A SPREADSHEET WK1 FORMAT FILE

IMPORT A DATABASE (SIMPLE) FORMAT ATTRIBUTE FILE

IMPORT A LAMM FORMAT ATTRIBUTE FILE

IMPORT USA CENSUS STF 1A FILES FOR TRACT/BNA

IMPORT USA CENSUS STF 1A FILES FOR BLOCK GROUPS

IMPORT ATLAS DATA FILES

The data are in standard form so:

Select IMPORT A STANDARD FORMAT ATTRIBUTE FILE

give the input data file as OZ-A

give the output attribute file as OZ

3. The data files are now entered so -

If you use the Files Manager to look in the directory \OZDATA you will find

that there are two new files there:

OZ.ATT is the attribute file and

OZ.GEO is the geographic file.

You (almost) never give a full file name within OzGIS - the system appends

a file extension to the name according to the file type.
 

Example Zones Choropleth Map - ZONES.OZA

The most common application is the display of data such as Census data as coloured polygons, usually known as a chloropleth map. Here the processes necessary to display such data are described.

Census data enables you to display maps that show where people live who are of different nationalities, ages, income groups etc. These maps are used for applications such as retail marketing to find where potential customers are located or for government planning to decide where to build facilities like schools.

You will probably have a file of attribute data (such as population Census data) and a file of digitised boundary data for mapping (e.g. TIGER): We will look at the data data for Australia. There are two data files:

OZ-G.DAT are the digitised boundary data, (Australian Statistical Divisions)

OZ-A.DAT are the attribute data

An example of entering these data files was given above.

Both the attribute file and geographic file are called OZ. Different types of files can have the same name.

Execute OzGIS.

Choose the Map pulldown menu and select DISPLAY ZONES FOR AN ATTRIBUTE FILE

give the attribute file name as OZ or select OZ.GEO

The data are now processed, the map is displayed, and the next menu appears. You now have a default map with legend and distribution diagram. The legend has the numbers of zones in each class on the left and the class value ranges to the right of the coloured boxes.

Now investigate some of the options:

Choose the option Attribute-> DISPLAY THE NEXT SEQUENTIAL ATTRIBUTE

Select the option to Attribute->SELECT AN ATTRIBUTE FROM A LIST.

Select Class-> CHANGE THE NUMBER OF CLASSES.

change the number of classes to 10.

Select the option to Class->CHANGE THE QUANTISATION METHOD.

Another menu will appear.

USE EQUAL VALUE INTERVALS

USE QUANTILES

USE SELECTED CLASS INTERVALS

USE SELECTED NUMBER OF ZONES PER CLASS

USE REFINED EQUAL VALUE INTERVALS

USE PSEUDO CONTINUOUS-COLOUR

USE THE MEAN AND STD DEVIATION METHOD

USE THE NESTED MEANS METHOD

USE THE NATURAL BREAKS METHOD

USE SELECTED PERCENTILES

USE SELECTED CLASS RANGE PERCENTILES

USE INTERACTIVE SELECTION OF CLASS INTERVAL,

USE EQUIVALENCE CLASSES

USE CURRENT CLASS RANGES

USE CURRENT NO PER CLASS

These options are very important as they enable the map to show the data in a way relevant to the purpose of the analysis.

For example, to select deciles:

Choose USE QUANTILES and set the number of classes to 10. The legend will now describe the 10 colours in the map.

Choose the option to Analyse->DISPLAY ATTRIBUTE STATISTICS.

Basic statistics will be displayed in a window for the displayed map.

Click "Quit" to remove the window.

Choose the option to Analyse->LIST ZONES FOR CENTROIDS SELECTED WITH BOX-CURSOR.

This will enable the current values for the displayed zones to be listed. A cursor will appear on the screen which indicates the bottom left position.

Use the mouse to select the first corner of a rectangle. A box cursor then appears to select the other corner. All zones are listed that have a minimum bounding rectangle (MBR) that intersects the selected window.

Choose Control->Top Menu to return to the main menu.

Summary of basic mapping

You now have seen simple examples of the processes to produce maps.

1. you obtain your data as files in a standard format.

2. you usually set up a directory on the same disk as \OZGIS and put the data files there.

3. Use IMPORT from the top menu to read in the data files.

4. Use Map options to display.

But ......... this is very simple

You may want to do some data preparation before mapping.

You may have geographic data as line segments and need to form the polygons.

You may want to display other types of maps or diagrams.

You may want to output prepared maps to a printer, plotter or file.

and so on.

Bivariate zones map Example - BIVAR.OZA

Bivariate maps enable you to compare two variables. For example you may want to compare your sales figures with Census data for the type of people you think are your customers.

First you need a bivariate device file to obtain a suitable colour set. Use Data->Display device file to see the default colour set. You will notice that the single variate colours are a sequence but the bivariate colours are mixed up. Use Data->Change device file and select one of the C256B*.DEV files, say c256bv1.dev. Use Data->Display colours again, and you will see that the bivariate colours are now a 2 dimensional sequence.

Select DISPLAY BIVARIATE ZONES FOR TWO ATTRIBUTE FILES from the Map menu.

Use attribute files LOWE1 and LOWE2 and geographic file LOWE (both attribute files can be the same i.e. you only need one file).

Note the form of the legend; the primary attribute (first file, top description) is the vertical part of the legend.

The main mapping menu will now appear on the toolbar:

These are the major groups of options and will be descibed in later chapters.

Use Control->Top Menu to return to the top menu.

Zones & sites Example - ZONESITE.OZA

This type of map is for applications such as deciding where to put shopping centres, where different symbols can be used for e.g. existing centres, centres owned by different retail chains and proposed new centres.

This example shows that type of map and also how the geographic data displayed on a map can be extended and modified.

Select DISPLAY ZONES AND SITES FOR TWO ATTRIBUTE FILES from the top menu.

Select DISPLAY SITES AS SIZED SINGLE COLOUR SYMBOLS

Use the LOWE1 and LOWE2 attribute files again, and the LOWE zones geographic file.

Give the sites geographic file as LOWE-S1.

This displays a file with polygons coloured for one attribute and symbols sized for the other. Now we can add more sites.

Choose REGIONS from the map menu, and then use DISPLAY MORE QUANTISED SITES ON A REGION. Give the next sites geographic file as LOWE-S2. Use symbol number 2 (number one is already used).

You will have a coloured zones map with different sized symbols according to the attribute values and different symbols for the two files.

Geographic (GIS) maps Example - GIS.OZA

Maps can be displayed that show geographic data without attribute data i.e. polygons, lines, names at points and symbols at points. Hence you can display roads, town locations, soil polygons etc.

Where the data are preclassified, feature codes can be used to subset the files for display.

For example, display some of the Hawaii DLG files. These files came from the USGS, and after some cleaning up, were entered as DLG-3 data and the polygons formed using BUILD TOPOLOGY FROM LINE SEGMENTS.

This example will display several of the files and show how feature codes can be used to subset the data displayed.

Select GIS from the top menu.

The next menu allows you to define a map according to the main file of geographic data that you have. You can add other data to the map as overlays

later:

DISPLAY LINE SEGMENTS FROM A GEOGRAPHIC FILE

DISPLAY MARKERS AT POINTS FROM A GEOGRAPHIC FILE

DISPLAY NAMES AT POINTS FROM A GEOGRAPHIC FILE

DISPLAY POLYGONS FROM A GEOGRAPHIC FILE

DISPLAY LINE SEGMENTS FOR FEATURE CODES

DISPLAY MARKERS AT POINTS FOR FEATURE CODES

DISPLAY NAMES AT POINTS FOR FEATURE CODES

DISPLAY POLYGONS FOR FEATURE CODES

Select DISPLAY POLYGONS FROM A GEOGRAPHIC FILE and use file HAWDLGWB, which is the outlines of the islands. Use any polygon number, give some text for the legend (e.g. "Islands") and use the no boundaries default.

The overlays menu will be used to add other geographic data:

OVERLAY LINE SEGMENTS FROM GEOGRAPHIC FILE

OVERLAY MARKERS FOR SITES IN GEOGRAPHIC FILE

OVERLAY NAMES FOR SITES IN GEOGRAPHIC FILE

UNDERLAY POLYGONS FROM GEOGRAPHIC FILE

OVERLAY LINE SEGMENTS FOR FEATURE CODES

OVERLAY MARKERS FOR SITES FOR FEATURE CODES

OVERLAY NAMES FOR SITES FOR FEATURE CODES

UNDERLAY POLYGONS FOR FEATURE CODES

DEFINE MAP REGIONS

CHANGE LEGEND

DISPLAY TEXT

SAVE DISPLAY AS A FILE

Select UNDERLAY POLYGONS FOR FEATURE CODES. Use file HAWDLGAB which is administrative boundaries. The file has feature codes in the range 900103 to 900108. Give the range as 900103 to 900103 and use polygon number say 4.

You will notice that a new menu item REMOVE POLYGONS UNDERLAY appears. A feature of the OzGIS system is that menus are dynamic and reflect the current status.

Select OVERLAY LINE SEGMENTS FOR FEATURE CODES. Use file HAWDLGRD which is roads. The file has feature codes in the range 2905001 to 2905041. Select a subset e.g. 2905000 to 2905020. Give the legend text as "roads".

Select OVERLAY LINE SEGMENTS FROM GEOGRAPHIC FILE. Use file HAWDLGST which is streams. Give the legend text as streams. The administrative boundaries go outside the island coastlines so you may want to redraw the island outlines by overlaying line segments for file HAWDLGWB.

Select OVERLAY NAMES FOR SITES IN GEOGRAPHIC FILE. Give the file HAWDLGWB. The polygon names will be displayed (the area numbers from the DLG file). Usually a points file would be used that has the actual names.

Select Text->TYPE IN A LINE OF TEXT, type in a title e.g. "HAWAII", and position it at the top of the map. Note that if you regenerate the map the polygons are drawn first, and then line segments, symbols and finally names. Within each type they are displayed in the order specified. If a mistake is made overlays can be removed.

You can change the view of the map: Select Region->SELECT WINDOW WITH THE BOX CURSOR.

Use "Top Menu" to return to the top level geographic map menu.

A similar set of options are available for overlaying data on other types of maps. For example you may want to overlay roads or town names on a Census data map.

Diagrams Example - DIAG.OZA

Distributions, sorted values and quantisation results can be displayed as full screen diagrams for one or two attribute files. Scatter diagrams can be displayed for two files.

For example, to display two histograms for two attributes: Choose DIAGRAMS from the top menu. The menu enables you to choose the type of diagram:

DISPLAY VALUES HISTOGRAM FOR AN ATTRIBUTE FILE

DISPLAY QUANTISATION HISTOGRAM FOR AN ATTRIBUTE FILE

DISPLAY DISTRIBUTION HISTOGRAM FOR AN ATTRIBUTE FILE

DISPLAY VALUES HISTOGRAM FOR TWO ATTRIBUTE FILES

DISPLAY QUANTISATION HISTOGRAM FOR TWO ATTRIBUTE FILES

DISPLAY DISTRIBUTION HISTOGRAM FOR TWO ATTRIBUTE FILES

DISPLAY SCATTER DIAGRAM FOR TWO ATTRIBUTE FILES

We will display two attributes, so a bivariate device file should be used. Choose Data->CHOOSE DEVICE FILE and select a file e.g. c256bv2.dev

Choose DISPLAY DISTRIBUTION HISTOGRAM FOR TWO ATTRIBUTE FILES Use LOWE1 and LOWE2 files.

Next choose FEATURES from the main menu.

Now add some statistics lines:

Choose ADD STATISTICS TO DIAGRAM. A new menu appears:

DISPLAY MEAN & STD DEVIATION

DISPLAY MEDIAN

DISPLAY REGRESSION POLYNOMIAL (for scatter diagrams)

Try the DISPLAY MEAN & STD DEVIATION option (and others if you like).

You can change attributes and quantisation in the usual ways.

By now you will have realised that there are many options available down a multitude of menu paths.

USA Census / TIGER Overlays Example - WASH.OZA

Some sample files are supplied with the system for Washington DC. These were supplied by the US Census Bureau, and would usually be obtained on CD-ROM.

The attribute file is WASHTRACT and was created by entering the first file off the STF1A CD-ROM (the original file was called STF1A0DC.DBF). This file contains about 40 of the 1990 Census variables extracted for tract/BNAs.

Three geographic files are supplied. These came from the CD-ROM files for Washington DC. The files for records type 1 (endpoints) and type 2 (shapes) were processed. The files were simplified (thinned) to reduce the size.

WASHTRACT was created by extracting census boundaries for the tract/BNAs with the IMPORT DATA FILES option, thinning with the PREPARE DATA FOR DISPLAY option, and finally using the BUILD TOPOLOGY option.

WASHRAIL is a lines file of railroads created by extracting for feature codes 200 to 252 in the data entry process.

WASHROAD is a lines file of all roads created by extracting for feature codes 100 to 148 in the data entry process.

These files can be used to demonstrate the use of overlays:

First select Map->DISPLAY ZONES FOR AN ATTRIBUTE FILE to display a zones map using attribute file WASHTRAC and geographic file WASHTRAC. This gives a standard choropleth map for 1990 Census data for Washington at tract/BNA level.

The Overlay menu offers options for several types of overlays:

OVERLAY LINE SEGMENTS FROM A GEOGRAPHIC FILE

OVERLAY MARKERS FOR SITES IN GEOGRAPHIC FILE

OVERLAY NAMES FOR SITES IN GEOGRAPHIC FILE

UNDERLAY POLYGONS FROM GEOGRAPHIC FILE

OVERLAY LINE SEGMENTS FOR FEATURE CODES

OVERLAY MARKERS FOR SITES FOR FEATURE CODES

OVERLAY NAMES FOR SITES FOR FEATURE CODES

UNDERLAY POLYGONS FOR FEATURE CODES

Now select Overlay->OVERLAY MARKERS FOR SITES IN GEOGRAPHIC FILE, use the same geographic file, select marker 1, give the legend text as TRACTS.

A series of markers will be displayed. The locations are the points within the standard zones/polygon file built with Prepare->BUILD ZONES so are the approximate centroids of the polygons.

Next select Overlay->OVERLAY NAMES FOR SITES IN GEOGRAPHIC FILE, and use the same geographic file in a similar way to display the tract codes. The names here are the zone names. You could of course use any file with different locations and names e.g. town names.

Now add a line segments overlay. Select Overlay->OVERLAY LINE SEGMENTS FROM A GEOGRAPHIC FILE. Use the file WASHRAIL to display railroads.

You could now do the same for the roads file washroads.geo. Try subsetting for feature codes as follows:

Select OVERLAY LINE SEGMENTS FOR FEATURE CODES. Use a different line number each time and try a range 110 to 138 first to display primary, secondary and country roads. Then try a range 140 to 148 to display neighbourhood roads. TIGER file feature codes are defined in this manual.

Building Zones Example

The procedure to generate polygons from line segments can be demonstrated with most of the geographic data files:

First input the geographic data file and give it a temporary name:

Select Import->IMPORT GEOGRAPHIC FILES and then IMPORT A STANDARD FORMAT

GEOGRAPHIC FILE. Use the test data file LOWE-G and give the new file name as TEMP1.

Next line simplify the line segments to drop points:

Select Prepare->PROCESS GEOGRAPHIC FILES and then SIMPLIFY (THIN) LINE SEGMENTS. The input file is the one just entered i.e. TEMP1 and output the new one as TEMP2. Simplify according to the size of the final map on the screen

e.g. give a value of 100 to throw away a lot of the data points e.g. if you have a super VGA at 1024 X 768 you could use 750.

Now build the polygons structure from the lines.

Select Prepare->BUILD TOPOLOGY FROM LINE SEGMENTS from the top menu

The menu is:

BUILD ZONES FROM LINE SEGMENTS INTO NEW GEOGRAPHIC FILE

BUILD ZONES FROM LINE SEGMENTS INTO NEW DATA FILE

BUILD LINES FROM LINE SEGMENTS INTO NEW GEOGRAPHIC FILE

BUILD LINES FROM LINE SEGMENTS INTO NEW DATA FILE

The usual option is BUILD ZONES FROM LINE SEGMENTS INTO NEW GEOGRAPHIC FILE.

Give the input geographic file as the simplified file TEMP2 and output it as TEMP3.

Use the defaults for other questions.

Finally display the result (attribute file LOWE1 and geographic file TEMP3) by using the Map->DISPLAY ZONES FOR AN ATTRIBUTE FILE menu option.

Projections Example

Suppose you have entered a file that you know is UTM for zone number 20 and you want to convert it to Lambert Conformal. Conversion is two steps, UTM to Lat/Long and then Lat/Long to Lambert.

Use the menu options in Prepare->Map projections.

First write the UTM definition into the header of the file. Select CHOOSE FROM PROJECTION SET 1 from the menu, and then select U.T.M. and give the zone number. Then select WRITE PROJECTION DEFINITION INTO GEOGRAPHIC FILE and give the name of your file.

Your file will now be defined as UTM by having the file header updated.

Now choose TRANSFORM PROJECTION FILE TO LAT / LONG and give the file names to generate a temporary file (called say TEMP) in latitude / longitude from your original file.

Then use CHOOSE FROM PROJECTION SET 1 again and choose LAMBERT CONFORMAL CONIC.

Then using TRANSFORM LAT / LONG FILE TO PROJECTION will give you the desired file in Lambert Conformal from the lat/long file to a new file.
 

Location/Allocation Example

Suppose there are three breweries in Australia and you want to know a good place to build another one.

Select Application->Site Location Allocation.

Give the geographic file name as OZ and the attribute file as OZ.

Choose an appropriate attribute - obviously "Beer consumption", and chosse 4 sites.

Give a name for the generated geographic file, say BREWERY

A solution will be displayed.

Now select Site->Give site a name and give the fourth site the name NEW BREWERY

Now for each of the existing sites (SITE001 to SITE003) choose Site->Digitise fixed location for a site and choose a location with the mouse.

You have now specified the locations of the three existing breweries and fixed them at those locations. The new brewery site is still mobile.

Finally use one of the algorithms from the Algorithm menu to generate a solution.

The solution can be used for further mapping.
 

First Site Catchment example

Select Applications->Site catchment definition.

Give the geographic file as CANBL81 (Canberra local government areas)

Select Define-> INCLUDE SITES FROM A CATCHMENT FILE

Give the catchment file as catch

A set of site catchments in Canberra will be displayed for a set of catchments that were previously defined.

Notes

You need a geographic zones file, and an attribute file of demographic data (typically Census data).

The attribute used will relate to the project e.g. to site child-care centres you may use 0 to 4 year olds.

The base map zones cannot have any missing data.

The following demonstration files are supplied:

Second Site Catchment example - CATCH.OZA

Suppose you want to analyse some shopping centre sites in Canberra and you have a geographic file of boundaries called CANBL81, a geographic file of suburb names called ACTSUBUB and a file of Census data for the zones called CANBL81.

Select Applications->Site catchment definition.

The catchments are defined relative to a base map, and there is the concept of a current set of sites being worked on. So give the geographic file as CANBL81. The base map is displayed.

First of all the shopping centre catchments have to be defined, so select Define

The following menu appears:

ADD A NEW SITE

DELETE A SITE

RENAME A SITE

REPOSITION SITE LOCN, NAME OR SYMBOL

MODIFY SITE CONTOURS

SEARCH GEOG FILE FOR SITES INSIDE A CONTOUR

CHANGE DISPLAYED REGION

TEMPORARYILY OVERLAY OTHER CATCHMENT FILE ON BASE MAP

OVERLAY GEOGRAPHIC FILES ON BASE MAP

DISPLAY ALL CURRENT SITES

INCLUDE SITES FROM CATCHMENT FILE

INCLUDE POINTS FROM GEOGRAPHIC FILE

INCLUDE POLYGONS FROM GEOGRAPHIC FILE

DISPLAY TEXT

OUTPUT TO CATCHMENT FILE

OUTPUT TO CATCHMENT FILE AND EXIT

Next display the suburb names by selecting Define->OVERLAY GEOGRAPHIC FILES and then OVERLAY SITE NAMES FROM A GEOGRAPHIC FILE. Give the file name as ACTSUBUR

The names are to help "navigate" so are not really necessary. You might also display roads (if you have the data).

You may also want to use the CHANGE DISPLAYED REGION option to change the part of Canberra that is displayed.

Now a new set of catchments can be defined (you can read in an old set) Select ADD A NEW SITE, which displays the menu:

ADD NEW SITE, CURSOR POSN

ADD NEW SITE, TYPED POSN

Sites are initially defined as circles. You provide a name, the radius of the circle, and a weight. Suppose it has been decided as a starting point the 75% of people living within a 5KM radius of a shopping centre will buy all their groceries there. So select ADD NEW SITE, CURSOR POSN for each site

You can define several sites and modify them in several ways e.g. add more contours.

Finally use Defgine->OUTPUT TO CATCHMENT FILE to store the site definitions.

Now the first version of the catchments have been defined, the proportions of the underlying base polygons that are within the contours can be calculated for each site and the weights applied.

Select GENERATE CATCHMENT FILE ZONES AND WEIGHTS

Give the names of the base zones geographic file as CANBL81 (it could be something else) and the name of the catchment file. The polygons and the contours are now intersected to find the areas of the common parts and the catchment file is updated for the list of zones and weights for each site.

Now the mapping data has to be output to files for mapping: Select Assemble, which gives the menu:

INCLUDE SITES FROM CATCHMENT FILE

CHANGE SYMBOL DISPLAY LOCATION

CHANGE NAME DISPLAY LOCATION

CHANGE DISPLAYED REGION

OUTPUT ZONES AND WEIGHTS TO COMBINE FILE

AMALGAMATE ATTRIBUTE DATA FOR COMBINE FILE

OUTPUT GEOGRAPHIC FILE FOR SYMBOLS AND CONTOUR DISPLAY

OUTPUT GEOGRAPHIC FILE FOR SITE NAMES AND OFFSET LINES

First select INCLUDE SITES FROM CATCHMENT FILE and give the catchment files as CATCH (you could input several files). This is an example file of defined catchments.

Now generate a geographic file for mapping the sites by selecting Assemble->OUTPUT GEOGRAPHIC FILE FOR SYMBOLS AND CONTOUR DISPLAY and giving a file name as say SITES.

Then select Assemble->OUTPUT GEOGRAPHIC FILE FOR SITE NAMES AND OFFSET LINES and give a file name, say NAMES.

Now accumulate the attribute data for the sites:

First select Assemble->OUTPUT ZONES AND WEIGHTS TO COMBINE FILE and give the file as SITECOMB (dont overwrite the example file COMB!). The combine file will contain the list of zones for each site and the weights.

Select Assemble->AMALGAMATE ATTRIBUTE DATA FOR COMBINE FILE

The attribute file is that for the base zones L81 and the combine file is SITECOMB. Give the output attributes as SITES.

You can now map the site data, so return to the top menu and select Map

You now have the two main files for mapping, a points file called SITES and the related attribute file SITES.

You could now select Map->DISPLAY SITES FOR AN ATTRIBUTE FILE to map the data. However, you can also display the original base map data at the same time: Select Map->DISPLAY ZONES AND SITES FOR TWO ATTRIBUTE FILES

The map is now displayed, with the site symbols on top of the base map.

Now add the contour lines by selecting Overlay-> OVERLAY LINE SEGMENTS FROM A GEOGRAPHIC FILE. Give the file as SITES.