Czech Association for Geoinformation

Metainformation Database System (MIDAS)

What is MIDAS?

Czech Association for Geoinformation (CAGI) is now undertaking a project of building a metainformation system consisting of descriptive data about available datasets of geodata in the Czech Republic. The main reason for building this system arose from the fact that until now there exists no functional GI-related metainformation system compatible with European standards in the Czech Republic. Seeing advances in state sector in this area as problematic and slow-moving until now, CAGI as a representative of GI users and providers decided according to its mission and aims to create and carry on MIDAS (Metainformation Database System) which should provide a possibility to easily find required information about existing geodata in the Czech Republic.

Key drivers

Main reasons for decision to build MIDAS can be seen as following (they are very similar or same to those in other countries):

• raising knowledge about existing datasets held by private and state organisations,
• providing efficient and widely used mean of information provision for data providers,
• integration of information about available datasets to one place which can be easily accessed,
• gaining direct or indirect benefits for individuals and organisations,
• raising overall awareness thanks to benefits that metadata brings.

Requirements on MIDAS

Based on the wide discussion among CAGI members and on analysis of users needs, the following basic requirements on MIDAS were identified:

• the system should consist of metadata about geodata in the Czech Republic at the level of datasets,
• the system should contain as wide spectrum of data sources as possible,
• the system should be freely available to anyone at no cost,
• first version (pilot version) should function at the end of 1999 at the latest,
• the system should be based on European standards (CEN/TC 287) to ensure compatibility with other national systems and to guarantee possibility of easy conversion or adaptability to future final European standards,
• the system should be built as open to enable enlargement of its contents and structure while at the same time offering integrated and intuitive interface for efficient search of information.

The work on MIDAS begun at the end of 1998 by establishing a working group from CAGI members and other specialists working in the field of subject matter. This group prepared base document called "Metainformation system of CAGI - project proposal" (only in Czech) which defined draft and process of MIDAS realisation together with financial balance sheet. After that, the system definition and implementation of CEN draft standards into data model followed and the programming phase has begun. The first "beta version" of MIDAS system is already available on the Internet (through www site of CAGI, http://www.cagi.cz/), but is still not fully functional. Also, the user interface will be significantly changed.

Contents of MIDAS

Due to very limited financial and human resources inside CAGI, the board decided to concentrate in the first (pilot) phase to collect metadata about datasets at the national level. Our estimations of number of existing national-level datasets is about 100-150 in the whole Czech Republic. With co-ordination and support of The Office for the State Information System, CAGI will guarantee collecting and possible maintenance of metadata this year.

However the resources for collecting data by CAGI are limited, the system can be filled with data at the regional (i.e. district) level. This is enabled by Internet "forms" by which regional data holders can insert their metadata on-line after registration.

After finishing the pilot phase it is supposed to insert metadata about analog (paper) maps and more detailed data about datasets with prospects to go to the level of geographic objects and its attributes.

To ensure the most possible usefulness of MIDAS, extensive administrative and citation data together with those spatially oriented are also collected. They include namely:

• data about individuals - persons (administrators of datasets, contact persons etc.),
• data about organisations (firms and institutions managing and/or owning datasets, etc.),
• data about literature concerted with datasets - will be continually extended to the available GI-related literature.

These data will be collected together with other data on integrated forms (on-line or printed). CAGI expects that the first metadata will come from private sector - CAGI members and selected state institutions (ministries and its service organisations).

Functions of MIDAS

As mentioned above, MIDAS will have public interface through World Wide Web which is generally recognised as the today's most developing media.

Functions of MIDAS can be divided into three levels.

At the top level they are:

• two-level representation of search results - basic (abstract) and detailed information on metadata,
• tracking of user activities within system and other statistics,
• providing integrated user interface to all parts of the system.

At the dataset level they are:

• input and maintenance - adding new records, updating and deleting of existing records,
• queries - based on dataset description, administrative data and spatial extent,
• visualisation and download of dataset samples.

At the level of supplement features they are:

• graphical representation of dataset position and extent, dataset search by selecting geographic area in the map of CR,
• detailed information about organisations and their bindings,
• detailed information about literature.

How MIDAS works

Due to limited financial resources CAGI decided to build the system in the first phase on non-commercial software basis.

Linux was selected as an operating system that MIDAS runs on. This system is available for free and is fully comparable with other commercial operating systems. Linux is also transparent system so it is possible to manage the whole system over the Internet via Telnet session.

With support of universities-CAGI members, CAGI has the possibility to use two widespread HTTP servers - Microsoft Internet Information Server (IIS) and Apache which is programmed within a GNU project. Although both servers are available for free (IIS is supplied together with MS Windows NT server), Apache was chosen because of its availability on both Linux and MS Windows platforms.

At the field of database management systems there are two freely available products - MySQL and PostgreSQL. MySQL was selected for its usability and relatively easy management.

Existing differences in component object models of WWW browsers led to decision not to use any client-side dependency problem solution of user interface. PHP, a powerful object-oriented scripting language with integrated database functions, is used on server side. PHP is available as a module of HTTP server or as CGI program.

The result which is delivered to a client, is "pure" HTML code with a little part of JavaScript that is supposed to be used only temporarily until final version is released .

However CAGI will operate this system in near future, the possibilities of transfer to other authority (the Office for State Information System is supposed) and/or software or hardware platform are considered.

Future plans

Enhancements proposed within MIDAS include:

• multilingual interface allowing querying and access to metadata in Czech and English languages (English metadata includes now only overview and title of dataset),
• creation of thesauri for geoinformation,
• transformation of MIDAS from relational to object - relational data model,
• enhancement of graphical map search capabilities,
• on-line geodata ordering.

Contacts

Czech Association for Geoinformation
Italská 34, 120 00 Praha 2, Czech Republic
Phone/fax: +420 2 2225 2291
E-mail: cagi@seznam.cz

Bronislava Horakova
Phone: +420 603 510458
E-mail: b.horakova@email.cz

Josef Hnojil
E-mail: hnojil@fsv.cvut.cz

Jan Růžička
Phone: +420 69 6995470
E-mail: jencekruzicka@hotmail.com