NAME

       r3.univar  - Calculates univariate statistics from the non-null 3d cells of a raster3d map.

KEYWORDS

       raster3d, voxel, statistics

SYNOPSIS

       r3.univar
       r3.univar help
       r3.univar    [-get]    input=name     [zones=name]      [output=name]      [percentile=float[,float,...]]
       [fs=character]   [--verbose]  [--quiet]

   Flags:
       -g
           Print the stats in shell script style

       -e
           Calculate extended statistics

       -t
           Table output format instead of standard output format

       --verbose
           Verbose module output

       --quiet
           Quiet module output

   Parameters:
       input=name
           Name of input raster3d 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

       fs=character
           Field separator
           Special characters: space, comma, tab
           Default: |

DESCRIPTION

       r3.univar calculates the univariate statistics for raster3d maps.  This  includes  the  number  of  cells
       counted,  minimum  and  maximum  cell  values,  range,  arithmetic  mean,  population  variance, standard
       deviation, and coefficient of variation. 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.

TODO

       mode, skewness, kurtosis

SEE ALSO

         g.region,  r.univar,  r.average, r.median, r.mode, r.quantile, r.sum, r.series, r3.stats, v.rast.stats,
       r.statistics, 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: 2012-08-14 02:11:23 -0700 (Tue, 14 Aug 2012) $

       Full index

       © 2003-2013 GRASS Development Team

GRASS 6.4.3                                                                                    r3.univar(1grass)