v.normal(1grass)

💅 v.normal — the GRASS User's Manual page, bestie edition ✨

okay so you're in the GRASS User's Manual, and this page is all about v.normal (it's a 1grass module, iykyk). she tests for normality for vector points. that's the whole vibe. 🦋

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✨ NAME ✨

okay so v.normal — it runs tests for normality on vector points. that's it, that's the job. 💖

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🎀 KEYWORDS 🎀

vector, statistics, points, point pattern

(yeah she's tagged and everything 🏷️)

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🌸 SYNOPSIS 🌸

v.normal
v.normal --help
v.normal [-rl] map=name  [layer=string]  tests=range[,range,...]
column=name  [--help]  [--verbose]  [--quiet]  [--ui]

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🚩 Flags 🚩 — the lil switches, no cap

• -r — use only the points that are chillin' in the current region. stay in your lane bestie 💅
• -l — checks lognormality instead of normality. plot twist!! 🔥
• --help — prints the usage summary. the classic. 🙈
• --verbose — verbose module output, so she tells you everything 🗣️
• --quiet — quiet module output. shhh 🤫
• --ui — forces the GUI dialog to launch. fancy mode on ✨

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🧚 Parameters 🧚 — the stuff you actually gotta fill in

• map=name [required] — name of the vector map. (or a data source for direct OGR access, if that's your thing 🫶)
• layer=string — layer number or name. so basically, vector features can have category values in different layers, and this number decides which layer to use. when you're doing direct OGR access, this is the layer name instead. Default: 1
• tests=range[,range,...] [required] — lists of tests, 1 through 15. like, for example: 1,3-8,13. pick your fighters 🎮
• column=name [required] — name of the attribute column. tell her where the numbers live 📊

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💖 DESCRIPTION 💖

v.normal computes tests of normality on vector points. periodt. she looks at your points and she judges whether they're normal (statistically speaking, bestie, not like, personality-wise 😭).

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👑 NOTES 👑

the tests that v.normal performs are indexed below ⬇️ and the ones she actually runs are specified by giving an index, ranges of indices, or multiple thereof. so you can be picky about it, she supports that.

1. Sample skewness and kurtosis
2. Geary's a-statistic and an approximate normal transformation
3. Extreme normal deviates
4. D'Agostino's D-statistic
5. Modified Kuiper V-statistic
6. Modified Watson U^2-statistic
7. Durbin's Exact Test (modified Kolmogorov)
8. Modified Anderson-Darling statistic
9. Modified Cramer-Von Mises W^2-statistic
10. Kolmogorov-Smirnov D-statistic (modified for normality testing)
11. Chi-Square test statistic (equal probability classes) and the number of degrees of freedom
12. Shapiro-Wilk W Test
13. Weisberg-Binghams W'' (similar to Shapiro-Francia's W')
14. Royston's extension of W for large samples
15. Kotz Separate-Families Test for Lognormality vs. Normality

likeee fifteen whole tests. she ate. 💅✨

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🌈 EXAMPLE 🌈

okay so say you wanna compute the sample skewness and kurtosis, Geary's a-statistic and an approximate normal transformation, extreme normal deviates, and Royston's W for the random vector points. here's the lil routine, copy it exactly bestie:

g.region raster=elevation -p
v.random random n=200
v.db.addtable random column="elev double precision"
v.what.rast random rast=elevation column=elev
v.normal random tests=1-3,14 column=elev

no cap, that's it. 🍓

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🦋 SEE ALSO 🦋

• v.univar

go give her a lil visit too, she's iconic 👑

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🫶 AUTHORS 🫶

James Darrell McCauley <darrell@mccauley-usa.com>, when he was at: Agricultural Engineering Purdue University

(we stan an academic era 🎓✨)

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💜 SOURCE CODE 💜

available at: v.normal source code (history)

latest change: Friday Feb 07 19:16:09 2025 in commit: a82a39f673b97fafcfce1604dc3e6015cb96487a

Main index | Vector 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 was GRASS 8.5.0, v.normal(1grass), last touched Friday Feb 07 19:16:09 2025 — stay normal (or lognormal, we don't judge) 💖✨🦋