v.normal(1grass) GRASS GIS User's Manual v.normal(1grass)
NAME
v.normal - Tests for normality for vector points.
KEYWORDS
vector, statistics, points, point pattern
SYNOPSIS
v.normal
v.normal --help
v.normal [-rl] map=name [layer=string] tests=range[,range,...] col-
umn=name [--help] [--verbose] [--quiet] [--ui]
Flags:
-r
Use only points in current region
-l
Lognormality instead of normality
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog
Parameters:
map=name [required]
Name of vector map
Or data source for direct OGR access
layer=string
Layer number or name
Vector features can have category values in different layers. This
number determines which layer to use. When used with direct OGR ac-
cess this is the layer name.
Default: 1
tests=range[,range,...] [required]
Lists of tests (1-15)
E.g. 1,3-8,13
column=name [required]
Name of attribute column
DESCRIPTION
v.normal computes tests of normality on vector points.
NOTES
The tests that v.normal performs are indexed below. The tests that are
performed are specified by giving an index, ranges of indices, or mul-
tiple thereof.
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
EXAMPLE
Compute the sample skewness and kurtosis, Geary’s a-statistic and an
approximate normal transformation, extreme normal deviates, and Roys-
ton’s W for the random vector points:
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
SEE ALSO
v.univar
AUTHOR
James Darrell McCauley <darrell@mccauley-usa.com>,
when he was at: Agricultural Engineering Purdue University
SOURCE CODE
Available at: v.normal source code (history)
Accessed: unknown
Main index | Vector index | Topics index | Keywords index | Graphical
index | Full index
© 2003-2022 GRASS Development Team, GRASS GIS 7.8.7 Reference Manual
GRASS 7.8.7 v.normal(1grass)
Generated by dwww version 1.14 on Wed Dec 25 10:02:06 CET 2024.