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NAME

       r3.neighbors   -  Makes  each  voxel value a function of the values assigned to the voxels
       around it, and stores new voxel values in an output 3D raster map

KEYWORDS

       raster3d, algebra, voxel, statistics, aggregation, neighbor, focal statistics, filter

SYNOPSIS

       r3.neighbors
       r3.neighbors --help
       r3.neighbors  input=name   output=name   method=string    [quantile=float]    window=x,y,z
       [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       --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:
       input=name [required]
           Name of input 3D raster map

       output=name [required]
           Name for output 3D raster map

       method=string [required]
           Aggregate operation
           Options: average, median, mode, minimum, maximum, range, stddev, sum, count, variance,
           diversity, interspersion, quart1, quart3, perc90, quantile

       quantile=float
           Quantile to calculate for method=quantile
           Options: 0.0-1.0

       window=x,y,z [required]
           The size of the window in x, y and z direction, values must be  odd  integer  numbers,
           eg: 3,3,3

DESCRIPTION

       r3.neighbors  looks  at each voxel in a 3D raster input map layer, and examines the values
       assigned to the voxel in a user-defined "neighborhood" around it.  It  outputs  a  new  3D
       raster  map in which each voxel is assigned a value that is a (user-specified) function of
       the values in that voxel’s neighborhood.  For example, each voxel in the output map  might
       be  assigned  a  value equal to the average of the values appearing in its 3 x 3 x 3 voxel
       "neighborhood" in the input map layer.

   OPTIONS
       The user must specify the names of the 3D raster map layers  to  be  used  for  input  and
       output, the method used to analyze neighborhood values (i.e., the neighborhood function or
       operation to be performed), and the moving window of the neighborhood.

       Neighborhood Operation Methods: The neighborhood operators  determine  what  new  value  a
       center  voxel  in  a  neighborhood will have after examining values inside its neighboring
       voxels.  Each voxel in a 3D raster map layer becomes the center voxel of a neighborhood as
       the  neighborhood window moves from voxel to voxel throughout the map layer.  r3.neighbors
       can perform the following operations:

       average
           The average value within the neighborhood.

       median
           The value found half-way through a list of the neighborhood’s values, when  these  are
           ranged in numerical order.

       mode
           The most frequently occurring value in the neighborhood.

       minimum
           The minimum value within the neighborhood.

       maximum
           The maximum value within the neighborhood.

       range
           The range value within the neighborhood.

       stddev
           The statistical standard deviation of values within the neighborhood.

       sum
           The sum of values within the neighborhood.

       variance
           The statistical variance of values within the neighborhood.

       diversity
           The number of different values within the neighborhood.

       interspersion
           The  percentage  of  voxels containing values which differ from the values assigned to
           the center voxel in the neighborhood, plus 1.

       Neighborhood Size: The neighborhood moving window specifies which  voxel  surrounding  any
       given  voxel  fall  into  the neighborhood for that voxel.  The window must be three comma
       separated odd integers. The  dimension  order  is:  x,y,z.   For  example:  the  parameter
       window=3,3,3 specifies a moving window (a cube) with 27 voxel.

NOTES

       The  r3.neighbors  program works in the current geographic region.  It is recommended, but
       not required, that the 3D resolution of the geographic region be the same as that  of  the
       3D raster map layer.

       r3.neighbors  doesn’t  propagate  NULLs,  but  computes  the aggregation over the non-NULL
       voxels in the neighborhood.

SEE ALSO

       g.region
       r.neighbors
       r3.mapcalc
       r3.stats
       r3.support

AUTHOR

       Soeren Gebbert

       Last changed: $Date: 2013-07-01 09:35:50 +0200 (Mon, 01 Jul 2013) $

SOURCE CODE

       Available at: r3.neighbors source code (history)

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