GRASS GIS: r.li.cwed

NAME

r.li.cwed - Calculates contrast weighted edge density index on a raster map

KEYWORDS

raster, landscape structure analysis, patch index

SYNOPSIS

r.li.cwed
r.li.cwed help
r.li.cwed map=name conf=string path=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
path=string: input file that contains the weight to calculate the index
output=name: Name for output raster map

DESCRIPTION

r.li.cwed (contrast weighted edge density) calculates the edge density between patch types specified:

with:

k: attribute
m: number of non-null attributes in the sampling area
eik: total length of edge in landscape between patch types i and k
dik: dissimilarity (edge contrast weight) between patch types i and k
Area: total landscape area

The input file have a row for each couple of patch type that we want to consider in the calculation. Each row must to have this syntax:
patchType1,patchType2,dissimilarityBetweenPatchType1andPatchType2

EXAMPLES

To calculate mean pixel attribute index on map my_map, using my_conf configuration file and saving results in my_out file run:

r.li.cwed map=my_map conf=my_conf path=my_file output=my_out

Example of input file:
12,16,0.65
44,123,0.32
56,12,0.54
23,66,0.99

NOTES

Do not use absolute path names for output files. They are raster if moving window disposition was selected, otherwise they are in ~/.r.li/output folder.
If the raster is full of null value it is considered to have 0 patch and CWED=0. If Area is 0 r.li.cwed returns -1. This is possible only if the map is masked.
If you want to have null values instead run

r.null setnull=-1 map=my_map

after index calculation.

REFERENCES

McGarigal, K., and B. J. Marks. 1995. FRAGSTATS: spatial pattern analysis program for quantifying landscape structure. USDA For. Serv. Gen. Tech. Rep. PNW-351.

AUTHORS

Serena Pallecchi student of Computer Science University of Pisa (Italy).
Commission from Faunalia Pontedera (PI), Italy (www.faunalia.it)

BUGS

Please send bugs reports to pallecch@cli.di.unipi.it

Last changed: $Date: 2007-02-08 08:33:52 -0800 (Thu, 08 Feb 2007) $

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