r.shade(1grass)

💅 r.shade 💅

okay bestie, welcome to r.shade, straight outta the GRASS User's Manual — and no, this is not the "throw some shade" module (sadly). This one drapes a color raster over a shaded relief or aspect map. It's giving glow-up for your elevation data. ✨

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✨ NAME ✨

r.shade — drapes a color raster over an shaded relief or aspect map. 🎨🫶

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🔑 KEYWORDS 🔑

raster, elevation, relief, hillshade, visualization

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🌈 SYNOPSIS 🌈

r.shade
r.shade --help
r.shade [-c] shade=name color=name output=name  [brighten=integer]
[brighten=integer] [bgcolor=name]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

wait no, let me not mess with that, here it is exactly:

r.shade
r.shade --help
r.shade [-c] shade=name color=name output=name  [brighten=integer]
[bgcolor=name]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

🚩 Flags

• -c — use colors from color tables for NULL values. lowkey a lifesaver when your data's got holes 🕳️
• --overwrite — allow output files to overwrite existing files (yes queen, replace it 💅)
• --help — print usage summary
• --verbose — verbose module output (she's talkative 👑)
• --quiet — quiet module output (she's mysterious 🦋)
• --ui — force launching GUI dialog

🎀 Parameters

• shade=name [required] — name of shaded relief or aspect raster map. this is the texture, the rizz, the shadow 💜
• color=name [required] — name of raster to drape over relief raster map. typically, this raster is elevation or other colorful raster 🍓
• output=name [required] — name of shaded raster map (your masterpiece ✨)
• brighten=integer — percent to brighten. options: -99-99, default: 0. negative values darken it btw, it's giving contrast control 🌙
• bgcolor=name — color to use instead of NULL values. either a standard color name, R:G:B triplet, or "none" 🌈

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💖 DESCRIPTION 💖

so like, r.shade will drape a color raster map over a shaded relief map. and honestly? in place of shaded relief, any raster map can be used, including aspect or slope. periodt.

the color raster map is usually an elevation raster map with a colorful color table (as opposed to gray scale color table). however, any raster map can be used — including categorical raster maps. no gatekeeping here, bestie. the result is a raster map created from elevation and the shade raster. 🎨

comparing to creating shaded relief as semi-transparent overlay on the color raster map, this module gives result with more saturated colors. it ate. 🔥

the input for this module can be created for example using r.slope.aspect or r.relief. iykyk.

⚠️ NULL values are propagated by default, so if any of the two input rasters contains NULL cell, NULL will be also in the output.

if the -c flag is used and cell in color raster is NULL, just shade color is used. if cell in shade raster is NULL, shading effect is not applied and original colors are used. if the bgcolor option is used, a NULL value in any input raster will be, in the output, replaced by the given color. 🌸

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📝 NOTES 📝

refer to the r.his help page for more details — r.shade is literally a frontend to that module, with the addition of brightness support similar to the one provided by d.shade. 💅

👀 but note: the brightness is not implemented in the same way as for d.shade, and the results might be different. r.shade is using the method described in the r.his manual page. so bestie, don't @ me when your brightness looks different. 😭

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🧚 EXAMPLES 🧚

in this example, the aspect map in the North Carolina sample dataset is used to hillshade the elevation map:

g.region raster=aspect -p
r.shade shade=aspect color=elevation output=elevation_aspect_shaded
d.mon wx0
d.rast elevation_aspect_shaded

in this next example, a shaded relief raster map is created and used to create a colorized hillshade raster map for later use:

g.region raster=elevation
r.relief input=elevation output=elevation_shaded_relief
r.shade shade=elevation_shaded_relief color=elevation \
    output=elevation_relief_shaded
d.mon wx1
d.rast elevation_relief_shaded

interesting visualizations can be created using different color tables for elevation raster map, for example using haxby color table. 🌈✨

Figure: a detail of raster created by applying shading effect of shaded relief (hillshade) to elevation raster map from North Carolina dataset elevation map.

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👀 SEE ALSO 👀

r.his, d.his, d.shade, g.pnmcomp, r.slope.aspect, r.relief

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👑 AUTHORS 👑

• Hamish Bowman
• Vaclav Petras, NCSU GeoForAll Lab
• Inspired by d.shade and manual for r.his.

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💻 SOURCE CODE 💻

available at: r.shade source code (history)

latest change: Friday Feb 07 19:16:09 2025 in commit: a82a39f673b97fafcfce1604dc3e6015cb96487a

Main index | Raster index | Topics index | Keywords index | Graphical index | Full index

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and that's a wrap, bestie!! 🎀 this was GRASS 8.5.0 Reference Manual energy, and the source/version + date moment is © 2003-2026 GRASS Development Team, GRASS 8.5.0 Reference Manual — slay, go drape some rasters 💖✨🦋