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NAME - Calculates contrast weighted edge density index on a raster map


raster, landscape structure analysis, patch index

SYNOPSIS --help input=name config=name path=name output=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]


Allow output files to overwrite existing files

Print usage summary

Verbose module output

Quiet module output

Force launching GUI dialog


Name of input raster map

Configuration file

Name of file that contains the weight to calculate the index

Name for output raster map

DESCRIPTION (contrast weighted edge density) calculates the edge density between patch types specified:


  • 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 contains a row for each couple of patch type that we want to consider in the calculation. Each row must be saved using this syntax:


Do not use absolute path names for the config and output file/map parameters. If the "moving window" method was selected in g.gui.rlisetup, then the output will be a raster map, otherwise an ASCII file will be generated in the folder C:\Users\userxy\AppData\Roaming\GRASS7\\output\ (MS-Windows) or $HOME/.grass7/ (GNU/Linux).

If the sample area contains only NULL values it is considered to have 0 patch and CWED=0. If Area is 0 returns -1. This is only possible if the map is masked.
If you want to change these -1 values to NULL, run subsequently on the resulting map:

r.null setnull=-1 input=my_map
after index calculation.


To calculate the contrast weighted edge density index on map my_map, using my_conf configuration file (previously defined with g.gui.rlisetup) and saving results in my_out, run: input=my_map conf=my_conf output=my_out \


Example for input "weights.csv" file:


SEE ALSO - package overview


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


Serena Pallecchi student of Computer Science University of Pisa (Italy).
Commission from Faunalia Pontedera (PI), Italy (
Markus Metz


Available at: source code (history)

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GRASS 7.8.5