r.li.mpa(1grass)

💖 r.li.mpa 💖

okay bestie, gather round, because we're talking about r.li.mpa from the GRASS User's Manual (that's the 1grass manual section, iykyk) — it calculates mean pixel attribute index on a raster map ✨

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🌸 KEYWORDS 🌸

raster, landscape structure analysis, patch index — yes she's a landscape-structure-analysis girlie 🦋

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✨ SYNOPSIS ✨

r.li.mpa
r.li.mpa --help
r.li.mpa input=name config=name output=name  [--overwrite]  [--help]
[--verbose]  [--quiet]  [--ui]

🎀 Flags:

• --overwrite — bestie this lets output files overwrite existing files, so like, be aware 👀
• --help — prints the usage summary, your little cheat sheet 💅
• --verbose — verbose module output, she's chatty and we love that
• --quiet — quiet module output, she's giving mysterious 🤫
• --ui — forces the GUI dialog to launch, for the visual learners 🖥️

🧚 Parameters:

• input=name [required] — name of input raster map, no skips allowed
• config=name [required] — configuration file, also required, periodt
• output=name [required] — name for output raster map, yep required too

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👑 DESCRIPTION 👑

r.li.mpa (mean pixel attribute) crunches the average value of the attribute of all the non-null cells in the sampling area, like this:

with:

• i: attribute
• m: number of non-null attributes in the sampling area
• wi: number of cells of attribute i
• size: size of sampling area (in cells)

there she is, the math, the moment, the whole vibe 📐✨

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💀 NOTES 💀

• 🚫 Do not use absolute path names for the config and output file/map parameters. Just don't, bestie.
• If the "moving window" method was selected in g.gui.rlisetup, then the output will be a raster map — otherwise an ASCII file will be generated in the folder C:\Users\userxy\AppData\Roaming\GRASS8\r.li\output\ (MS-Windows) or $HOME/.grass8/r.li/output/ (GNU/Linux).
• If the input raster map contains only NULL values then r.li.mpa considers to have 0 patches.
• If area is 0 r.li.mpa returns -1; it is possible only if the raster is masked. (the masking really said "not today" 🙈)
• If you want to change these -1 values to NULL, run subsequently on the resulting map:

r.null setnull=-1 input=my_map

after index calculation. do it after, not before, okay? timing is everything 💅

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🌈 EXAMPLES 🌈

To calculate the mean pixel attribute index on map my_map, using my_conf configuration file (previously defined with g.gui.rlisetup) and saving results in my_out, run:

r.li.mpa input=my_map conf=my_conf output=my_out

Forest map (Spearfish sample dataset) example:

g.region raster=landcover.30m -p
r.mapcalc "forests = if(landcover.30m >= 41 && landcover.30m <= 43,1,null())"
r.li.mpa input=forests conf=movwindow7 out=forests_mpa_mov7
r.univar forests_mpa_mov7

Forest map (North Carolina sample dataset) example:

g.region raster=landclass96 -p
r.mapcalc "forests = if(landclass96 == 5, 1, null() )"
r.li.mpa input=forests conf=movwindow7 out=forests_mpa_mov7
# verify
r.univar forests_mpa_mov7
r.to.vect input=forests output=forests type=area
d.mon wx0
d.rast forests_mpa_mov7
d.vect forests type=boundary

she ate that entire workflow, no crumbs, no cap 🔥

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🫶 SEE ALSO 🫶

• r.li (package overview)
• g.gui.rlisetup

go read those too, they're the supporting cast and they deserve their flowers 🌸

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🍓 REFERENCES 🍓

McGarigal, K., and B. J. Marks. 1995. FRAGSTATS: spatial pattern analysis program for quantifying landscape structure. USDA For. Serv. Gen. Tech. Rep. PNW-351. (PDF)

yes we cite our sources, academic integrity is main character energy ⭐

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💜 AUTHORS 💜

• Serena Pallecchi, student of Computer Science University of Pisa (Italy).
• Commission from Faunalia Pontedera (PI), Italy (www.faunalia.it)
• Markus Metz

shoutout to the icons who built this 💖

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🔥 SOURCE CODE 🔥

Available at: r.li.mpa source code (history)

Latest change: Friday Apr 17 01:04:26 2026 in commit: 32a143358df26b2e518b03c7e0d79541e8d1e5b1

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

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and that's the whole page bestie 🎀 this was pulled from the GRASS 8.5.0 Reference Manual, © 2003-2026 GRASS Development Team, and the last time anybody touched this commit was Friday Apr 17 01:04:26 2026 — so it's fresh, it's current, it's giving maintained. go calculate some mean pixel attributes, ily, bye 💅✨🦋