r.compositegrass - Online in the Cloud

PROGRAM:

NAME

r.composite - Combines red, green and blue raster maps into a single composite raster
map.

KEYWORDS

raster, composite, RGB

SYNOPSIS

r.composite
r.composite --help
r.composite [-dc] red=name green=name blue=name [levels=integer] [level_red=integer]
[level_green=integer] [level_blue=integer] output=name [--overwrite] [--help]
[--verbose] [--quiet] [--ui]

Flags:
-d
Dither

-c
Use closest color

--overwrite
Allow output files to overwrite existing files

--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>

levels=integer
Number of levels to be used for each component
Options: 1-256
Default: 32

level_red=integer
Number of levels to be used for <red>
Options: 1-256

level_green=integer
Number of levels to be used for <green>
Options: 1-256

level_blue=integer
Number of levels to be used for <blue>
Options: 1-256

output=name [required]
Name for output raster map

DESCRIPTION

This program combines three raster maps to form a composite RGB map. For each input map
layer, the corresponding component from the map’s color table is used (e.g. for the red
map, the red component is used, and so on). In general, the maps should use a grey-scale
color table.

NOTES

The default number of intensity levels for each component is 32, resulting in a total of
32768 possible colors (equivalent to 15 bits per pixel). If significantly more levels than
this are used, not only will r.composite take longer to run, but displaying the resulting
layer with d.rast will also be significantly slower.

Floyd-Steinberg dithering is optionally used with the -d flag.

EXAMPLES

RGB composite of three satellite bands
Color composite of a LANDSAT scene (North Carolina sample dataset):
g.region raster=lsat7_2002_10
r.composite blue=lsat7_2002_10 green=lsat7_2002_20 red=lsat7_2002_30 \
output=lsat7_2002_rgb

RGB composite with dithering
Creating a composite RGB raster using 32 color levels per layer, with dithering:
r.composite -d red=elevation.r green=elevation.g blue=elevation.b \
output=elev.composite

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