trusty (1) r.li.patchdensity.1grass.gz

NAME

       r.li.patchdensity  - Calculates patch density index on a raster map, using a 4 neighbour algorithm

KEYWORDS

       raster, landscape structure analysis, patch index

SYNOPSIS

       r.li.patchdensity
       r.li.patchdensity help
       r.li.patchdensity map=name conf=string output=name  [--overwrite]  [--verbose]  [--quiet]

   Flags:
       --overwrite
           Allow output files to overwrite existing files

       --verbose
           Verbose module output

       --quiet
           Quiet module output

   Parameters:
       map=name
           Name of input raster map

       conf=string
           Configuration file

       output=name
           Name for output raster map

DESCRIPTION

       r.li.patchdensity is a patch index for r.li 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.

EXAMPLES

       To calculate patch density index on map my_map, using my_conf configuration file (previously defined with
       r.li.setup) and saving results in the raster map my_out, run:
       r.li.patchdensity 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 r.li.setup):
       r.li.patchdensity forests conf=movwindow7 out=forests_p_dens7
       d.rast.leg forests_p_dens7
       r.to.vect forests out=forests feature=area
       d.vect forests type=boundary

NOTES

       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, r.li.patchdensity returns -1. This is only possible
       if the raster is masked.

SEE ALSO

       r.li package overview
       r.li.daemon
       r.li.setup

AUTHORS

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

       Full index

       © 2003-2013 GRASS Development Team