Landscape Editor - Surface Definition Tools

Surface Definition Tools
The Height Definition tool buttons on the toolbar are activated when the Heights/Water layer is selected from the Current Layer drop down list in the Parameter Display area.

The Spot height tool displays the height of the selected grid point. Enter either null or a height value. If entering several points at the same height the Default height tool can be used to set each grid point to the last height entered with the spot height tool.

The Manual contour trace tool is used to set a series of sample points along a line to be set to the same height. Typically this tool would be used to trace the contour lines on a bitmap loaded as background. The tool uses a combination of the left and right mouse buttons or clicks and double clicks. To start a contour press the left mouse button. You may now either move the mouse whilst holding down the button, or release the button and click again at another position. In both cases a red line highlights where the contour will be placed. Continue defining the contour using any combination of these actions until complete, then either double click the left button or click the right button. A dialog box prompts for the height of the contour.

The Auto-contour trace tool is also used to set a series of sample points along a line to be set to the same height. It traces the contour lines on a bitmap loaded as background, and behaves in a similar manner to the Manual contour trace. Your background bitmap must be black or colour detail on a white background. The auto-contour tool works by following a selected line. It is colour-sensitive, and give best results on scanned image if they are 'cleaned up' using a paint package an/or the Map Filter utility before use.

To start tracing a contour press the left mouse button over a contour line. The program will now proceed to follow the line over the image, reversing the line colour as it does so. On completion a dialog box prompts for the height of the contour. By default, the trace only follows pixels of exactly the same colour, however when using the tool to trace contours from background bitmaps with 256 colors or more you may find it useful to widen the range of colors recognized as belonging to the same contour. To do this use the color tolerance slider on the map page of the parameters notebook.

Blocks of grid points may be set to the same height using the Area heights tool. Click and drag using the left mouse button to define a rectangular area. On release a dialog prompts for a height (or null) to which all sample points within the area will be set.

Finally the Interpolate heights tool will interpolate the heights of undefined (null) grid points, and would typically be used after defining a representative sample of points. Interpolation is discussed in more detail separately.