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4 Modification and assignment of colortables

The values available in an image file are visually coded by GRASS via a colortable. After creating a raster image the rastermap is assigned to - with few exceptions - the default colortable ``rainbow''. There are several ways to create a map-specific colortable.

One of the standard colortables can be assigned using the module r.colors:

r.colors map=raster map color=standard table
r.colors map=raster map color=special table

color options: aspect,grey,grey.eq,grey.log,byg,byr,gyr,rainbow,ramp,
               random,ryg,wave,rules
rules options: aspect,bcyr,byg,byr,elevation,evi,grey,gyr,rainbow,ramp,
               ryg,slope,srtm,terrain,wave

By indicating the variable rules we can assign our own colortable:

r.colors map=geology color=rules << EOF
4 100 200 0
5 255 130 7
6 100 129 187
7 222 180 39
9 43 18 200
EOF

For transferring the colortable from one rastermap to another or for assigning an individual or already specified colortable use the module r.colors with the parameter "rast":

r.colors rastermap rast=orig_rastermap

The newly assigned colortable can be visualized via the module d.colortable:

d.colortable rastermap