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 12:29:50 +0100 (Tue, 08 Nov 2011) $
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