GRASS GIS manual: r.composite

Note: A new GRASS GIS stable version has been released: GRASS GIS 7.8, available here.
Updated manual page: here

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
NOTES
EXAMPLES
- RGB composite of three satellite bands
- RGB composite with dithering
SEE ALSO
AUTHOR

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

AUTHOR

Glynn Clements

Last changed: $Date$

SOURCE CODE

Available at: r.composite source code (history)