GRASS GIS: r.univar

NAME

r.univar - Calculates univariate statistics from the non-null cells of a raster map.

KEYWORDS

raster, statistics

SYNOPSIS

r.univar
r.univar help
r.univar [-ge] map=name[,name,...] [percentile=integer[,integer,...]] [--verbose] [--quiet]

Flags:

-g: Print the stats in shell script style
-e: Calculate extended statistics
--verbose: Verbose module output
--quiet: Quiet module output

Parameters:

map=name[,name,...]: Name of input raster map(s)
percentile=integer[,integer,...]: Percentile to calculate (requires extended statistics flag); Options: 0-100; Default: 90

DESCRIPTION

r.univar calculates the univariate statistics of a raster map. This includes the number of cells counted, minimum and maximum cell values, range, arithmetic mean, population variance, standard deviation, and coefficient of variation. If the -e extended statistics flag is given the 1st quartile, median, 3rd quartile, and given percentile are calculated. If the -g flag is given the results are presented in a format suitable for use in a shell script.

NOTES

As with most GRASS raster modules, r.univar operates on the cell array defined by the current region settings, not the original extent and resolution of the input map. See g.region.

This module can use large amounts of system memory when the -e extended statistics flag is used with a very large region setting. If the region is too large the module should exit gracefully with a memory allocation error. Basic statistics can be calculated using any size input region.

TODO

mode, skewness, kurtosis

AUTHORS

Hamish Bowman, Otago University, New Zealand
Extended statistics by Martin Landa

Last changed: $Date: 2007-04-06 12:49:26 -0700 (Fri, 06 Apr 2007) $

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