r.colors.stddev - GRASS manual
Author: GRASS Development Team
Description: r.colors.stddev: Sets color rules based on stddev from a raster map's mean value.
Keywords: raster, color table

## NAME

r.colors.stddev - Sets color rules based on stddev from a raster map's mean value.

## KEYWORDS

raster, color table

## SYNOPSIS

r.colors.stddev
r.colors.stddev --help
r.colors.stddev [-bz] map=name [--help] [--verbose] [--quiet] [--ui]

### Flags:

-b
  Color using standard deviation bands
-z
  Force center at zero
--help
  Print usage summary
--verbose
  Verbose module output
--quiet
  Quiet module output
--ui
  Force launching GUI dialog

### Parameters:

map=name [required]
  Name of raster map

## DESCRIPTION

r.colors.stddev set raster map color rules based on standard deviations from a map's mean value, either as a continuous color gradient or in color bands per standard deviation (S.D.) from the mean.

With the color band option values less that 1 S.D. from the mean are colored green, within 1-2 S.D. are colored yellow, within 2-3 S.D. are colored red, and beyond 3 S.D. are colored black.

For a differences map there is an option to lock the center of the color table at zero. Values more than two S.D. below the mean will be colored blue; values below the mean but less than 2 S.D. away will transition to white, and above the mean the colors will similarly transition to full red at +2 S.D.

## EXAMPLE

North Carolina sample dataset:

    g.region raster=elevation -p
    r.colors.stddev elevation

Figure: Standard deviations from mean elevation

## SEE ALSO

r.colors, r.univar, v.colors

## AUTHOR

Hamish Bowman, Dunedin, New Zealand

## SOURCE CODE

Available at: r.colors.stddev source code (history)

Accessed: Monday May 11 17:55:43 2026

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