## DESCRIPTION

RGB stands for red, green, and blue. d.rgb visually combines three raster maps to form a color image. For each map, the corresponding component from the layer's color table is used (e.g. for the red layer, the red component is used, and so on). In general, the input raster maps should use a grey-scale color table.

## NOTES

d.rgb does not attempt to quantize the combined image into a fixed number of colors. Nor does it have an option to generate a composite layer. The image and raster maps will not display properly if the graphics device does not have a reasonable sampling of the RGB color-space.

If color quality of satellite image color composites seems to appear poor, run r.colors on the selected satellite channels.

Example:

    r.info -r image.1

    min=0
    max=255

    r.colors map=image.1 color=grey

    r.colors map=image.2 rast=image.1
    r.colors map=image.3 rast=image.1

Note: Future GRASS versions may do this for you automatically.

To write out the color composite to a R/G/B raster maps, use r.composite.

## EXAMPLE

    d.rgb red=image.1 green=image.2 blue=image.3

## SEE ALSO

d.colortable, d.his, r.blend, r.mapcalc, r.colors, r.composite

## AUTHOR

Glynn Clements

Last changed: $Date$