r.surf.random(1grass)

✨ r.surf.random — the GRASS User's Manual, bestie edition ✨

okay so welcome to r.surf.random, a lil module from the GRASS fam (that's the manual name babe, r.surf.random(1grass)) that literally just makes a raster surface map full of uniform random deviates in whatever range you feel like. no cap. 🎲💖

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🌈 NAME 🌈

r.surf.random — produces a raster surface map of uniform random deviates with a defined range. it's giving "chaos, but make it spatial" 💅

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🏷️ KEYWORDS 🏷️

raster, surface, random — yes those are the tags, and yes they're accurate, periodt.

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📜 SYNOPSIS 📜

r.surf.random
r.surf.random --help
r.surf.random [-i] output=name  [min=float]   [max=float]
    [seed=integer]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

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🚩 Flags 🚩

• -i — create an integer raster map. whole numbers only bestie, no decimals allowed 🧚
• --overwrite — lets output files overwrite existing files. use with intention okay, this one is powerful 👑
• --help — prints the usage summary. when you're lost, she's there 🫶
• --verbose — verbose module output. she tells you everything 💬
• --quiet — quiet module output. she tells you nothing 🤫
• --ui — force launching the GUI dialog. for the visual girlies 🎀

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🎛️ Parameters 🎛️

• output=name [required] — name for the output raster map. you MUST name your baby, there's no skipping this one 😭
• min=float — minimum random value. default: 0
• max=float — maximum random value. default: 100
• seed=integer — seed value for the random number generator. using the same seed ensures identical results, while a randomly generated seed produces different outcomes in each run. lowkey the most important knob here for reproducibility fr fr 🌱

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💫 DESCRIPTION 💫

so r.surf.random produces a raster map layer of uniform random deviates whose range can be expressed by the user. it's essentially the same as r.surf.gauss, but uses a linear random number generator instead. iconic sibling energy honestly 🌸

under the hood it uses the random number generator drand48() or rand(), depending on the user's platform. so whichever one your machine vibes with, that's the one you get 🦋

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🔥 EXAMPLE 🔥

first set up your region:

g.region -p n=228500 s=215000 w=630000 e=645000 res=10
r.surf.random out=random min=0 max=100
# check result
r.univar random

Figure: Random surface example (min: 10; max: 100)

with the histogram tool the cell values versus count can be shown. yes bestie, you can literally see the distribution and it's so satisfying 📊✨

Figure: Histogram of random surface example (min: 10; max: 100)

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👀 SEE ALSO 👀

r.random.surface, r.surf.contour, r.surf.fractal, r.surf.gauss, r.surf.idw, v.surf.rst

(the whole surf squad, go check them out, they ate 💅)

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👑 AUTHOR 👑

Jo Wood Midlands Regional Research Laboratory (ASSIST) University of Leicester October 1991

shoutout to Jo for real, an absolute legend since '91 🕰️💜

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📦 SOURCE CODE 📦

Available at: r.surf.random source code (history)

Latest change: Thursday May 08 20:58:05 2025 in commit: 4144ba81fa125e1549fc52e1cf5feb4fa004be8b

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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and that's the whole page bestie!! 🌈 this gorgeous lil manpage lives in GRASS 8.5.0, and we're sending it off with a mwah 💋 — go make some random surfaces, stay reproducible, and don't forget your seed 🍓✨