r.univar(1)

NAME
r.univar

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.

The r.quantile module will be significantly more efficient for calculating percentiles with large maps.

TODO
mode, skewness, kurtosis

SEE ALSO
g.region
r3.univar
r.univar.sh
r.average
r.median
r.mode
r.quantile
r.sum
r.series
r.stats
r.statistics
v.univar
v.univar.sh

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

Last changed: $Date: 2010-03-10 17:52:33 +0100 (Wed, 10 Mar 2010) $

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