r.blend - GRASS manual
Author: GRASS Development Team
Description: r.blend: Blends color components of two raster maps by a given ratio.
Keywords: raster, composite

## NAME

r.blend - Blends color components of two raster maps by a given ratio.

## KEYWORDS

raster, composite

## SYNOPSIS

r.blend
r.blend --help
r.blend [-c] first=name second=name output=basename [percent=float] [nprocs=integer] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

### Flags:

-c
  Combine resulting R,G,B layers into single output map
--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:

first=name [required]
  Name of first raster map for blending
second=name [required]
  Name of second raster map for blending
output=basename [required]
  Basename for red, green and blue output raster maps
percent=float
  Percentage weight of first map for color blending
  Options: 0-100
  Default: 50
nprocs=integer
  Number of threads for parallel computing
  0: use OpenMP default; >0: use nprocs; <0: use MAX-nprocs
  Default: 0

## DESCRIPTION

r.blend blends color components of 2 raster maps by a specified percentage of the first map.

## EXAMPLE

Blending the aspect map with the elevation map for a shaded map (North Carolina sample dataset):

    g.region raster=elevation
    r.relief input=elevation output=relief zscale=10
    r.blend -c first=elevation second=relief output=blend percent=75

Figure: Elevation blended with shaded relief

## SEE ALSO

d.shade, g.region, r.shade, r.colors, r.his, r.mapcalc, r.rgb, r.support

## AUTHORS

Unknown: probably CERL
Updated to GRASS 5.7 by Michael Barton, Arizona State University

## SOURCE CODE

Available at: r.blend source code (history)

Latest change: Thursday Nov 06 23:50:00 2025 in commit: f714bf80e54f853796854f03b5c86fd7f5b1cd9d

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