Color tables

From GRASS-Wiki
Jump to navigation Jump to search


Color tables live in $GISBASE/etc/colors (see SVN)




  • There is an online colormap repository with many fine GMT (and many others) gradients at
  • There are a number of command line tools for working with the GMT .cpt files at


Built in

The numeric values of following color tables can be found in the here

Colortable aspect.png

Colortable aspectcolr.png

Colortable bcyr.png

Colortable bgyr.png

Colortable byg.png

Colortable byr.png

Colortable celsius.png

Colortable corine clc.gcolors.png

Colortable curvature.png

Colortable differences.png

Colortable elevation.png

Colortable etopo2.png

Colortable evi.png

Colortable grey.png

Colortable grey1.0.png

Colortable grey255.png

Colortable gyr.png

Colortable haxby.png

Colortable ndvi.png

Colortable population.png

Colortable precipitation.png

Colortable rainbow.png

Colortable ramp.png

Colortable ryb.png

Colortable ryg.png

Colortable sepia.png

Colortable slope.png

Colortable srtm.png

Colortable terrain.png

Colortable wave.png


These user contributions can be found in the GRASS addons SVN repository

Colortable palette chl etc.gcolors.png

Colortable palette sst.gcolors.png

Colortable palette GMT ocean.gcolors.png

Colortable palette roygbiv.gcolors.png

Colortable palette high intensity.gcolors.png

Colortable palette low intensity.gcolors.png

  • The script used to create these thumbnails can be found on the discussion page.

Using GRASS color palettes in QGIS

Most of them can already be found there, you just have to hunt for them. In the raster layer properties window's style tab, select "Singleband pseudocolor" as the type, "Generate new color map", "New color ramp", for ramp type choose "cpt-city", change to the "Sort by Author" tab, and look for "grass". They can also be found in the QGIS section cpt-city's QGIS theme.

If there's a new set of color rules which are not in QGIS, you can prepare a .svg palette file for use with QGIS using the following commands. Consider to then open a ticket in the QGIS issue tracker asking them to add it (and attach the file of course to save someone some work :)

You will need the cptsvg command line tool from cptutils and the GRASS 6 addon module r.out.gmt.


 g.region n=100 s=0 w=0 e=100 res=1
 r.mapcalc "dummy = row()"
 r.colors dummy color=roygbiv
 r.out.gmt dummy out=roygbiv
 rm roygbiv.grd
 cptsvg --geometry=300x45 -o roygbiv.svg -v roygbiv.cpt
 r.colors dummy rules=~/grass/svn/grass-addons/grass6/raster/
 r.out.gmt dummy out=palette_sst
 rm palette_sst.grd
 cptsvg --geometry=300x45 -o palette_sst.svg -v palette_sst.cpt

You can then copy the resulting .svg file into /usr/share/qgis/resources/cpt-city-qgis-min/grass/ on Linux (or C:\Program Files\QGIS VERSION\apps\qgis\resources\cpt-city-qgis-min\grass\ on MS Windows).

Loading QGIS color palettes into GRASS

Currently the GRASS 6 addon module r.cpt2grass seems to hit a bug, but the general idea is to use the svgx command line program from the cptutils package, using GMT's .cpt color table format as a go-between:

 svgx --output dkbluered.cpt --type cpt  /usr/share/qgis/resources/cpt-city-qgis-min/h5/dkbluered.svg
 r.cpt2grass in=dkbluered.cpt output=dkbluered.gcolors