GENERATE_EQUAL_VAL_AREAS

The GENERATE_EQUAL_VAL_AREAS command allows for the generation of areas for regions of the same (or similar) color, elevation, or slope values from a loaded raster or elevation layer.

  • FILENAME - specifies the filename of the already loaded layer from which to generate the equal-value areas. This parameter can be listed more than once to specify multiple input files, like FILENAME="FILENAME_1" FILENAME="FILENAME_2".
  • LAYER_DESC - specifies the description to use for the layer
  • ATTR_NAME - specifies the name to use for the attribute holding the color, elevation, or slope that a particular area represents. If you leave this attribute off then no value attribute will be saved with each area.
  • ATTR_FORMAT - specifies a custom format string for creating the color attribute. This would be a C-style string with either a single number parameter or 3 for separate red, green, and blue. Usually you wouldn't specify this and the default would then just be the same as ATTR_FORMAT="RGB( %3d, %3d, %3d )".
  • AREA_TYPE - specifies the name of the area type to assign to the area features. See the Area Styles tab of the Configuration dialog for a list of available type names.
  • EQUAL_COLORS (raster only) - specifies the color(s) to create areas for. If you don't provide one of more colors all colors are matched on. The color(s) should be specified as RGB(<red>,<green>,<blue>). For example, to create areas for white, use EQUAL_COLORS=RGB(255,255,255). Optionally, if the image that you are creating areas for uses a palette for the colors, you can specify a palette index in the following format: INDEX(<0-based palette index>). For example, to make the second color in the palette transparent, use EQUAL_COLORS=INDEX(1). You can provide more than one color to match on by providing a semi-color separated list, like EQUAL_COLORS="RGB(0,255,0);RGB(255,0,0)" to match on blue and red.
  • COLOR_DIST - specifies how far from an exact match each color channel of a color value must be to be considered the same. By default a value of 0 is used which means exact matches only. If you want to break the entire color range into say 4 ranges for each color channel, use something like COLOR_DIST=32 as that would allow colors up to 32 away from each color channel value to match to a color.
  • ELEV_DIST - specifies how far from an exact match (in meters) each value must be to be considered the same. By default a value of 0 is used which means exact matches only. If you want to say split into area groups 10 meters in size, use ELEV_DIST=5. This would give you areas with values between -5 and 5 meters, 5 and 15 meters, etc.
  • SLOPE_DIST - specifies how far from an exact match (in degrees) each value must be to be considered the same. By default a value of 0 is used which means exact matches only. If you want to say split into area groups 10 degrees in size, use SLOPE_DIST=5. This would give you areas with values between 0 and 10 degrees, 10 and 20 degrees, etc.
  • FORCE_RGB - specifies that the attribute value for a color-based area will always be the full RGB color and not a palette index/name if available. Use FORCE_RGB=YES to enable.
  • FIX_INVALID - specifies whether or not the resulting areas should be split up into pieces if any invalid (i.e. self-intersecting) pieces are created. Use FIX_INVALID=YES to force the invalid areas to be fixed.

SAMPLE

This sample will generate equal-elevation areas of size 20 meters (10 meters on either side) from the specified DEM layer and store the elevation values in an attribute named ELEV for each area feature.

 GENERATE_EQUAL_VAL_AREAS FILENAME="C:\temp\export test\blue_springs_4_quads.dem" ELEV_DIST=10.0 ATTR_NAME="ELEV"