NAME

       d.rgb  - Displays three user-specified raster maps as red, green, and blue overlays in the
       active graphics frame.

KEYWORDS

       display, raster, RGB

SYNOPSIS

       d.rgb
       d.rgb help
       d.rgb [-ox] red=name green=name blue=name  [--verbose]  [--quiet]

   Flags:
       -o
           Overlay (non-null values only)

       -x
           Don't add to list of commands in monitor

       --verbose
           Verbose module output

       --quiet
           Quiet module output

   Parameters:
       red=name
           Name of raster map to be used for 'red'

       green=name
           Name of raster map to be used for 'green'

       blue=name
           Name of raster map to be used for 'blue'

DESCRIPTION

       RGB stands for red, green, and blue. This  program  visually  combines  three  raster  map
       layers to form a color image. For each layer, 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 layers should use a grey-scale color table.

OPTIONS

   Flags:
       -o
              Overlay  the  resulting  raster map layer onto whatever is already displayed in the
              active graphics frame. Any no-data areas in any of the named raster maps will  seem
              transparent,  and  reveal the underlying image previously displayed in the graphics
              frame. If the -o flag is  set,  only  cells  containing  non-null  values  will  be
              displayed  from the overlaid raster map. All other areas (i.e., the portions of the
              overlaid map that contain null values) will leave the underlying display untouched.

   Parameters:
       red=name
              Name of raster map layer to be used for RED component.

       green=name
              Name of raster map layer to be used for GREEN component.

       blue=name
              Name of raster map layer to be used for BLUE component.

NOTES

       This is a new version of d.rgb, which sends the data to the graphics monitor in true-color
       RGB  format.   Unlike  the  previous version, it 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 map layers 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=rules << EOF
       0 black
       255 white
       EOF
       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.

SEE ALSO

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

AUTHOR

       Glynn Clements

       Last changed: $Date: 2011-11-08 03:29:50 -0800 (Tue, 08 Nov 2011) $

       Full index

       © 2003-2013 GRASS Development Team