NAME

       r3.univar  - Calculates univariate statistics from the non-null cells of a 3D raster map.
       Statistics  include  number  of  cells  counted,  minimum  and maximum cell values, range,
       arithmetic mean, population variance, standard deviation, coefficient  of  variation,  and
       sum.

KEYWORDS

       raster3d, statistics, univariate statistics

SYNOPSIS

       r3.univar
       r3.univar --help
       r3.univar  [-get]  map=name  [zones=name]   [output=name]   [percentile=float[,float,...]]
       [separator=character]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -g
           Print the stats in shell script style

       -e
           Calculate extended statistics

       -t
           Table output format instead of standard output format

       --overwrite
           Allow output files to overwrite existing files

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       map=name [required]
           Name of 3D raster map

       zones=name
           3D Raster map used for zoning, must be of type CELL

       output=name
           Name for output file (if omitted or "-" output to stdout)

       percentile=float[,float,...]
           Percentile to calculate (requires extended statistics flag)
           Options: 0-100
           Default: 90

       separator=character
           Field separator
           Special characters: pipe, comma, space, tab, newline
           Default: pipe

DESCRIPTION

       r3.univar calculates the univariate statistics for a 3D raster  map.   This  includes  the
       number  of  cells  counted,  minimum  and  maximum  cell  values,  range, arithmetic mean,
       population variance, standard deviation, coefficient of variation, and sum. Statistics are
       calculated  separately  for every category/zone found in the zones input map if given.  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.  If the -t flag is given the results are presented  in
       tabular format with the given field separator. The table can immediately be converted to a
       vector attribute table which can then be linked to a vector,  e.g.  the  vector  that  was
       rasterized to create the zones input raster.

NOTES

       As  with most GRASS raster3d modules, r3.univar operates on the voxel array defined by the
       current 3d 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.

EXAMPLE

       Computing univariate statistics of a 3D raster with randomly generated values:
       # generate random map
       r3.mapcalc "random_0_1 = rand(0., 1)" -s
       # compute univariate statistics
       r3.univar map=random_0_1

TODO

       mode, skewness, kurtosis

SEE ALSO

        g.region, r.univar, r.mode, r.quantile, r.series, r3.stats,  r.statistics,  v.rast.stats,
       v.univar

AUTHORS

       Soeren Gebbert
       Code is based on r.univar from
       Hamish Bowman, Otago University, New Zealand
       and Martin Landa
       Zonal loop by Markus Metz

       Last changed: $Date: 2014-10-14 04:57:21 +0200 (Tue, 14 Oct 2014) $

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       © 2003-2016 GRASS Development Team, GRASS GIS 7.0.3 Reference Manual