r.what.color(1)

💖 r.what.color — the GRASS GIS manual, but make it make sense 💖

okay bestie, so this is r.what.color(1) from the GRASS GIS User's Manual, and it is genuinely one of the most useful little gremlins in the whole raster toolbox. it answers one very specific question: what color is this value in this map? and honestly? obsessed.

✨ 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

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💅 DESCRIPTION 💅

r.what.color outputs the color associated with user-specified category values in a raster input map. that's it, that's the whole vibe. you give it values, it gives you colors. main character energy fr fr.

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). no cap, that's just how it do.

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)"’

quick reminder bestie: those format strings are literal, curly quotes and all — copy them exactly or the whole thing gets messy 😭

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👀 SEE ALSO 👀

r.what

👑 AUTHOR 👑

Glynn Clements

📦 SOURCE CODE 📦

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

Accessed: Saturday Jan 17 05:41:06 2026

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© 2003-2025 GRASS Development Team, GRASS GIS 8.4.2 Reference Manual

that's the whole page babes, go query some colors 💖✨ and yeah, this was GRASS 8.4.2 — r.what.color(1) — ily, bye 🫶