r.what.color(1)

NAME
r.what.color - Queries colors for a raster map layer.

KEYWORDS
raster, querying, color table

SYNOPSIS
r.what.color
r.what.color --help
r.what.color [-i] input=string [value=float[,float,...]] [format=string] [--help] [--verbose] [--quiet] [--ui]

  Flags:

-i
    Read values from stdin

--help
    Print usage summary

--verbose
    Verbose module output

--quiet
    Quiet module output

--ui
    Force launching GUI dialog

  Parameters:

input=string [required]
    Name of existing raster map to query colors

value=float[,float,...]
    Values to query colors for

format=string
    Output format (printf-style)
    Default: %d:%d:%d

DESCRIPTION
r.what.color outputs the color associated with user-specified category values in a raster input map.

Values may be specified either using the values= option, or by specifying the -i flag and passing the values on stdin, one per line.

For each value which is specified, a line of output will be generated consisting of the category value followed by the color, e.g.:

r.what.color input=elevation.dem value=1500
1500: 223:127:31

If the input map is an integer (CELL) map, the category will be written as an integer (no decimal point), otherwise it will be written in floating point format (printf("%.15g") format).

If the lookup fails for a value, the color will be output as an asterisk, e.g.:

r.what.color input=elevation.dem value=9999
9999: *

If a value cannot be parsed, both the value and the color will be output as an asterisk, e.g.:

r.what.color input=elevation.dem value=bogus
*: *

The format can be changed using the format= option. The value should be a printf()-style format string containing three conversion specifiers for the red, green and blue values respectively, e.g.:

r.what.color input=elevation.dem value=1500 format=’%02x:%02x:%02x’
1500: df:7f:1f

If your system supports the %m$ syntax, you can change the ordering of the components, e.g.:

r.what.color input=elevation.dem value=1500 format=’%3$02x:%2$02x:%1$02x’
1500: 1f:7f:df

Common formats:

    •   Tcl/Tk: format="#%02x%02x%02x"

    •   WxPython: format=’"#%02x%02x%02x"’ or format=’"(%d,%d,%d)"’

SEE ALSO
r.what

AUTHOR
Glynn Clements

SOURCE CODE

Available at: r.what.color source code (history)

Accessed: Friday Nov 14 04:25:11 2025

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