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Note: A new GRASS GIS stable version has been released: GRASS GIS 7.4, available here.
Updated manual page: here

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


input=name [required]
Name of input raster map
config=name [required]
Configuration file
path=name [required]
Name of file that contains the weight to calculate the index
output=name [required]
Name for output raster map

Table of contents

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

rlicwed formula


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

Last changed: $Date: 2014-11-28 08:22:17 -0800 (Fri, 28 Nov 2014) $


Available at: source code (history)

Note: A new GRASS GIS stable version has been released: GRASS GIS 7.4, available here.
Updated manual page: here

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© 2003-2018 GRASS Development Team, GRASS GIS 7.2.3svn Reference Manual