r.blend(1grass)

💖 NAME 💖

r.blend — blends color components of two raster maps by a given ratio. (Yes bestie, this is the page straight out of the GRASS User's Manual, and we're gonna read it together.)

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🦋 KEYWORDS 🦋

raster, composite

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✨ SYNOPSIS ✨

okay so this is literally how you call it:

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 those resulting R, G, B layers into one single output map. one map. unified. iconic. 👑
• --overwrite — lets output files just bulldoze over existing files that are already sitting there. (use with intention, bestie 🫶)
• --help — prints you the usage summary, the lil cheat sheet.
• --verbose — verbose module output, i.e. it tells you everything that's happening. main character energy but for logs.
• --quiet — quiet module output. shhh. 🤫
• --ui — force-launches the GUI dialog, for when you want the clicky-clicky version.

🌸 Parameters 🌸

• first=name [required] — name of the first raster map you're blending. mandatory, no skipping.
• second=name [required] — name of the second raster map for blending. also mandatory. the duo. the pair. 💅
• output=basename [required] — basename for the red, green and blue output raster maps (so like, the base name that the three output maps get built from).
• percent=float — percentage weight of the first map for color blending.
  • Options: 0-100
  • Default: 50
• nprocs=integer — number of threads for parallel computing, because we love speed 🏃‍♀️
  • 0: use OpenMP default; >0: use nprocs; <0: use MAX-nprocs
  • Default: 0

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🌈 DESCRIPTION 🌈

r.blend blends the color components of 2 raster maps, using a specified percentage of the first map. that's it, that's the whole vibe check. two maps in, blended colors out.

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🍓 EXAMPLE 🍓

Blending the aspect map with the elevation map to make a shaded map — using the North Carolina sample dataset, periodt:

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. (gorgeous, no notes ✨)

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🧚 SEE ALSO 🧚

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

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👑 AUTHORS 👑

• Unknown: probably CERL — the mystery author era 😭
• Updated to GRASS 5.7 by Michael Barton, Arizona State University

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💜 SOURCE CODE 💜

Available at: r.blend source code (history)

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

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

© 2003-2026 GRASS Development Team, GRASS 8.5.0 Reference Manual

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okay that's the whole thing bestie 🫶 this page is from GRASS 8.5.0 (the GRASS Development Team's 2003-2026 copyright era, fr fr) — love that for us, now go blend some rasters 💅🌸