r.li.patchnum(1grass)

💅 r.li.patchnum (1grass) ✨

okay bestie, welcome to the GRASS User's Manual page for r.li.patchnum, and yes we're doing this together, grab a matcha 🍓

🌸 NAME 🌸

r.li.patchnum — calculates the patch number index on a raster map, and it does it using a 4 neighbour algorithm. that's the whole gig, she's niche and she's booked 💅

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👑 KEYWORDS 👑

raster, landscape structure analysis, patch index — iykyk 🦋

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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 — allow output files to overwrite existing files (she will simply replace what's there, no cap, so be careful 💀)
• --help — prints the usage summary, like a lil cheat sheet 🫶
• --verbose — verbose module output, she talks more
• --quiet — quiet module output, she talks less
• --ui — force launching GUI dialog, for when you want buttons instead of typing 🌈

🧚 Parameters:

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

all three are required, no skipping, no substitutions, we don't do that here ⭐

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💖 DESCRIPTION 💖

so r.li.patchnum calculates the "patch number index" as:

f(sample_area)= Patch_Number

the way that this index gets calculated?? it uses a 4 neighbour algorithm, which means diagonal cells are ignored when tracing a patch. like, four neighbours only, she doesn't look diagonally, periodt 🎀

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💀 NOTES 💀

• Do not use absolute path names for the config and output file/map parameters. just don't. absolute paths are not the vibe here.
• 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). pick your fighter 🦋
• if the sample area contains only NULL values then it is considered to have zero patches. empty girlie = no patches, that's just the rule ✨

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🌈 EXAMPLES 🌈

to calculate patch number 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.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) — the whole friend group 💜
• 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)

academic citation but make it iconic 🎀

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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)

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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okay and that's the page bestie 🫶 this is r.li.patchnum from the GRASS 8.5.0 Reference Manual, dated and versioned and copyrighted as © 2003-2026 GRASS Development Team, GRASS 8.5.0 — she's iconic, she's maintained, she ate, no crumbs 💅✨🌸