xenial (1) d.rgb.1grass.gz

NAME

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

KEYWORDS

       display, graphics, raster, RGB

SYNOPSIS

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

   Flags:
       -n
           Make null cells opaque

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       red=name [required]
           Name of raster map to be used for <red>

       green=name [required]
           Name of raster map to be used for <green>

       blue=name [required]
           Name of raster map to be used for <blue>

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 (see r.composite for that).  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  i.colors.enhance  on  the
       selected satellite channels.

       An alternative is the assignment of grey color tables to each band with r.colors:
       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

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

EXAMPLE

       Visual color composite of a LANDSAT scene (North Carolina sample dataset):
       g.region raster=lsat7_2002_10 -p
       d.rgb blue=lsat7_2002_10 green=lsat7_2002_20 red=lsat7_2002_30

SEE ALSO

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

AUTHOR

       Glynn Clements

       Last changed: $Date: 2014-12-28 16:45:01 +0100 (Sun, 28 Dec 2014) $

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