r.li.patchnum(1)

✨ r.li.patchnum ✨

ok bestie so this is a page from the GRASS GIS User's Manual (yes the whole manual, we're just vibing with one lil tool here) and it's all about r.li.patchnum 💖

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🌸 NAME 🌸

r.li.patchnum — it counts the patch number index on a raster map, and it does it with a 4 neighbour algorithm. that's the whole job. slay. 💅

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🎀 KEYWORDS 🎀

raster, landscape structure analysis, patch index 🦋

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✨ SYNOPSIS ✨

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

🌈 Flags:

• --overwrite — lets your output files just bulldoze over existing files. no cap.
• --help — prints the usage summary, i.e. the "what does this even do" moment
• --verbose — verbose module output, it yaps (affectionate)
• --quiet — quiet module output, it says nothing, main character silence 🤫
• --ui — forces the GUI dialog to launch

💜 Parameters:

• input=name [required] — the name of the input raster map
• config=name [required] — the configuration file
• output=name [required] — the name you want for the output raster map

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🦋 DESCRIPTION 🦋

ok so r.li.patchnum calculates the "patch number index" like this:

f(sample_area)= Patch_Number

and the way it gets there? 4 neighbour algorithm energy. that means when it's tracing a patch, diagonal cells are literally ignored. not invited. blocked. 🙈

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💀 NOTES 💀

bestie do NOT use absolute path names for the config and output file/map parameters. i'm so serious. 😭

if you picked the "moving window" method in g.gui.rlisetup, then your output is gonna be a raster map. if you didn't, you get an ASCII file generated in this folder instead:

• C:\Users\userxy\AppData\Roaming\GRASS8\r.li\output\ (MS-Windows)
• $HOME/.grass8/r.li/output/ (GNU/Linux)

also!! if the sample area has only NULL values, then it's considered to have zero patches. that's it, that's the rule. ✨

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🍓 EXAMPLES 🍓

wanna calculate patch number index on map my_map, using my_conf configuration file (which you already defined earlier with g.gui.rlisetup, obvi) and save the results in my_out? run:

r.li.patchnum input=my_map conf=my_conf out=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.patchnum input=forests conf=movwindow7 out=forests_patchnum_mov7
r.univar forests_patchnum_mov7

Forest map (North Carolina sample dataset) example: 🌳

g.region raster=landclass96 -p
r.mapcalc "forests = if(landclass96 == 5, 1, null() )"
r.li.patchnum input=forests conf=movwindow7 out=forests_patchnum_mov7
# verify
r.univar forests_patchnum_mov7
r.to.vect input=forests output=forests type=area
d.mon wx0
d.rast forests_patchnum_mov7
d.vect forests type=boundary

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👑 SEE ALSO 👑

• r.li — package overview
• g.gui.rlisetup

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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) 🫶

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🧚 AUTHORS 🧚

• Michael Shapiro - CERL (patch identification)
• Markus Metz (statistics)

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⭐ SOURCE CODE ⭐

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

Accessed: Saturday Jan 17 05:40:54 2026

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

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and that's the whole thing bestie 💖 this page is running on GRASS GIS 8.4.2</s> — nope wait, it's GRASS 8.4.2, part of the GRASS GIS 8.4.2 Reference Manual, © 2003-2025 GRASS Development Team, accessed Saturday Jan 17 05:40:54 2026. ate and left no crumbs. periodt. 💅✨🎀