r.li.renyi(1grass)

💖 r.li.renyi — the manual page, but make it make sense 💖

okay bestie, so r.li.renyi is a GRASS GIS module — part of the r.li family — and honestly? it's giving landscape ecologist main character energy. Let's get into it 💅

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✨ NAME ✨

r.li.renyi — calculates Renyi's diversity index on a raster map. That's it, that's the whole job, and she does it beautifully 🦋

🏷️ KEYWORDS 🏷️

raster, landscape structure analysis, diversity index — yes she contains multitudes 💜

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🌸 SYNOPSIS 🌸

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

🎀 Flags

• --overwrite — lets your output files just... overwrite existing files. no hesitation, no "are you sure", she simply replaces them 🙈
• --help — prints the usage summary, aka the "bestie explain" button
• --verbose — verbose module output, she tells you everything, unprompted, like a group chat at 2am
• --quiet — quiet module output, the opposite vibe, she says nothing and just works ✨
• --ui — forces the GUI dialog to launch, for when clicking > typing

🧚 Parameters

• input=name [required] — Name of input raster map. your map, your moment
• config=name [required] — Configuration file. the rules of the game
• alpha=string [required] — Alpha value is the order of the generalized entropy
• output=name [required] — Name for output raster map. name her something cute 💕

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💜 DESCRIPTION 💜

r.li.renyi calculates the "Renyi's diversity index" as:

with:

• H: Renyi entropy
• alpha: order of the generalized entropy
• i: patch type
• S: number of different patch types
• pi: proportional abundance of patch type i

periodt. that's the formula energy 🧮✨

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🔥 NOTES 🔥

okay so pay attention because this part is important:

Do not use absolute path names for the config and output file/map parameters. nope. don't do it. she will not vibe with that.

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). so like, know where your stuff is landing bestie 📁

Also, if the input raster map contains only NULL values then r.li.renyi returns NULL. she's honest about it. no cap 💀

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🌈 EXAMPLES 🌈

Example 1 — the basics

To calculate Renyi's diversity 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.renyi input=my_map conf=my_conf output=my_out alpha=0.6

Example 2 — Forest map (Spearfish sample dataset) 🍓

g.region raster=landcover.30m -p
r.mapcalc "forests = if(landcover.30m >= 41 && landcover.30m <= 43,1,null())"
r.li.renyi input=forests conf=movwindow7 out=forests_renyi_mov7_a06 alpha=0.6
r.univar forests_renyi_mov7_a06

Example 3 — Forest map (North Carolina sample dataset) 🦋

g.region raster=landclass96 -p
r.mapcalc "forests = if(landclass96 == 5, 1, null() )"
r.li.renyi input=forests conf=movwindow7 out=forests_renyi_mov7
# verify
r.univar forests_renyi_mov7
r.to.vect input=forests output=forests type=area
d.mon wx0
d.rast forests_renyi_mov7
d.vect forests type=boundary

look at that workflow, she ATE 👑

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👀 SEE ALSO 👀

• r.li (package overview) — the whole girl group
• g.gui.rlisetup — where you set your config up

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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)

(the classic. the blueprint. we respect her 🫶)

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💅 AUTHORS 💅

Luca Delucchi and Duccio Rocchini, Fondazione E. Mach (Italy), based on the r.li.shannon code developed by Serena Pallecchi, student of Computer Science University of Pisa (Italy).

like okay collaboration icons ✨

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💻 SOURCE CODE 💻

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

Latest change: Tuesday Apr 29 06:19:47 2025 in commit:

12f893be22c8aeda9b048070dde6a4a230791e2a

Indexes, if you're feeling navigational: Main index | Raster index | Topics index | Keywords index | Graphical index | Full index 🌟

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so yeah, that's r.li.renyi(1grass) from the GRASS 8.5.0 Reference Manual, © 2003-2026 GRASS Development Team — thanks for coming to my ted talk, now go compute some entropy bestie 💖✨🌸🦋💅