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NAME   -  Calculates patch density index on a raster map, using a 4 neighbour


       raster, landscape structure analysis, patch index

SYNOPSIS help map=name conf=string output=name  [--overwrite]  [--verbose]  [--quiet]

           Allow output files to overwrite existing files

           Verbose module output

           Quiet module output

           Name of input raster map

           Configuration file

           Name for output raster map

DESCRIPTION is a patch index for suite.  It calculates the function:
       f(sample_area) = (Patch_Number/Area) * 1000000
        that is 1000000 by number of patch for area unit.  This index is  calculated  using  a  4
       neighbour algorithm.


       To  calculate  patch  density  index  on  map  my_map,  using  my_conf  configuration file
       (previously defined with and saving results in the raster map my_out, run: map=my_map conf=my_conf out=my_out

       Example for Spearfish forest areas:
       g.region rast=landcover.30m -p
       # extract forested areas:
       r.category landcover.30m
       r.mapcalc "forests=if(landcover.30m >= 41 && landcover.30m <=43,1,null())"
       # patch density (7x7 moving window defined in forests conf=movwindow7 out=forests_p_dens7
       d.rast.leg forests_p_dens7 forests out=forests feature=area
       d.vect forests type=boundary


       A map of NULL values is considered to have zero patches.
       If you want to have null values instead run

       r.null setnull=0 map=my_out

       after index calculation.
       If raster area is 0, returns -1. This is only possible
       if the raster is masked.

SEE ALSO package overview


       Claudio Porta and Lucio Davide Spano, students of Computer Science
       University of Pisa (Italy).
       Commission from Faunalia Pontedera (PI) (

       Full index

       © 2003-2013 GRASS Development Team