Ubuntu Manpage: r.statistics - Calculates category or object oriented statistics.

Provided by: grass-doc_7.8.2-1build3_all

NAME

       r.statistics  - Calculates category or object oriented statistics.

KEYWORDS

       raster, statistics, zonal statistics

SYNOPSIS

       r.statistics
       r.statistics --help
       r.statistics  [-c]  base=name  cover=name method=string output=name  [--overwrite]  [--help]  [--verbose]
       [--quiet]  [--ui]

   Flags:
       -c
           Cover values extracted from the category labels of the cover map

       --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:
       base=name [required]
           Name of base raster map

       cover=name [required]
           Name of cover raster map

       method=string [required]
           Method of object-based statistic
           Options: diversity, average, mode, median, avedev, stddev, variance, skewness,  kurtosis,  min,  max,
           sum
           diversity: Diversity of values in specified objects in %%
           average: Average of values in specified objects
           mode: Mode of values in specified objects
           median: Median of values in specified objects
           avedev: Average deviation of values in specified objects
           stddev: Standard deviation of values in specified objects
           variance: Variance of values in specified objects
           skewness: Skewnes of values in specified objects
           kurtosis: Kurtosis of values in specified objects
           min: Minimum of values in specified objects
           max: Maximum of values in specified objects
           sum: Sum of values in specified objects

       output=name [required]
           Resultant raster map

DESCRIPTION

r.statistics is a tool to analyse exploratory statistics of a categorical "cover layer" according to how
it intersects with objects in a "base layer". A variety of standard statistical measures are possible
(called "zonal statistics" in some GIS). All cells in the base layer are considered one object for the
analysis. For some applications, one will first want to prepare the input data so that all areas of
contiguous cell category values in the base layer are uniquely identified, which can be done with
r.clump.
The available methods are the following:

• average deviation

• average

• diversity

• kurtosis

• maximum

• median

• minimum

• mode

• skewness

• standard deviation

• sum

• variance
The calculations will be performed on each area of data of the cover layers which fall within each unique
value, or category, of the base layer.

Setting the -c flag the category labels of the covering raster layer will be used. This is nice to avoid
the GRASS limitation to integer in raster maps because using category values floating point numbers can
be stored.

All calculations create an output layer. The output layer is a reclassified version of the base layer
with identical category values, but modified category labels - the results of the calculations are stored
in the category labels of the output layer.

NOTES

       For  floating-point cover map support, see the alternative r.stats.zonal.  For quantile calculations with
       support for floating-point cover maps, see the alternative r.stats.quantile.

EXAMPLES

       Calculation of average elevation of each field in the Spearfish region:
       r.statistics base=fields cover=elevation.dem out=elevstats method=average
       r.category elevstats
       r.mapcalc "fieldelev = @elevstats"
       r.univar fieldelev

AUTHOR

       Martin Schroeder, Geographisches Institut Heidelberg, Germany

SOURCE CODE

       Available at: r.statistics source code (history)

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       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual