## 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.

## SEE ALSO

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

## AUTHORS

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

Last changed: $Date: 2011-08-16 02:13:05 -0700 (Tue, 16 Aug 2011) $