NAME

       r.stats.zonal   -  Calculates  category  or  object oriented statistics (accumulator-based
       statistics).

KEYWORDS

       raster, statistics, zonal statistics

SYNOPSIS

       r.stats.zonal
       r.stats.zonal --help
       r.stats.zonal  [-cr]  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

       -r
           Create reclass map with statistics as category labels

       --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:  count,  sum,  min,  max, range, average, avedev, variance, stddev, skewness,
           kurtosis, variance2, stddev2, skewness2, kurtosis2
           count: Count of values in specified objects
           sum: Sum of values in specified objects
           min: Minimum of values in specified objects
           max: Maximum of values in specified objects
           range: Range of values (max - min) in specified objects
           average: Average of values in specified objects
           avedev: Average deviation of values in specified objects
           variance: Variance of values in specified objects
           stddev: Standard deviation of values in specified objects
           skewness: Skewness of values in specified objects
           kurtosis: Kurtosis of values in specified objects
           variance2: (2-pass) Variance of values in specified objects
           stddev2: (2-pass) Standard deviation of values in specified objects
           skewness2: (2-pass) Skewness of values in specified objects
           kurtosis2: (2-pass) Kurtosis of values in specified objects

       output=name [required]
           Resultant raster map

DESCRIPTION

       r.stats.zonal is a tool to analyse  exploratory  statistics  of  a  floating-point  "cover
       layer"  according  to  how  it  intersects  with  objects  in a "base layer". A variety of
       standard statistical measures are possible.  This type of analysis is often  called  zonal
       statistics.   The  zones  are  specified  as  the  base  raster map and the statistics are
       computed from cells in the cover raster map.   Notably,  the  output  of  this  module  is
       spatial: The resulting values are recorded as cell values in the output raster map.

NOTES

       r.stats.zonal  is  intended to be a partial replacement for r.statistics, with support for
       floating-point cover maps at the expense  of  not  supporting  quantiles.  For  this,  see
       r.stats.quantile.

EXAMPLE

       In  this  example, the raster polygon map zipcodes in the North Carolina sample dataset is
       used to calculate zonal raster statistics using the elevation raster map:
       g.region raster=zipcodes -p
       # pixel count in zipcode areas
       r.stats.zonal base=zipcodes cover=elevation method=count output=zipcodes_elev_count
       r.colors zipcodes_elev_count color=gyr -g
       # average elevation in zipcode areas
       r.stats.zonal base=zipcodes cover=elevation method=average output=zipcodes_elev_avg
       r.colors zipcodes_elev_avg color=elevation -g

       Figure: ZIP code map on the left shows ZIP code areas, elevation map the respective values
       per  pixel,  zonal  statistics  map on the right shows the average elevation per zone (all
       maps: spatial subset).

SEE ALSO

           •   r.stats.quantile for computing quantiles in zones (objects in base raster map),

           •   r.quantile for computing quantiles of a whole raster map,

           •   r.statistics for categorical (integer) zonal statistics,

           •   r.univar for zonal statistics with textual (non-spatial) output,

           •   v.vect.stats for statistics of vector points in vector areas.

AUTHOR

       Glynn Clements

SOURCE CODE

       Available at: r.stats.zonal source code (history)

       Accessed: Thursday Aug 01 11:30:22 2024

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       © 2003-2024 GRASS Development Team, GRASS GIS 8.4.0 Reference Manual