r.li.cwed.1grass man page

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


raster, landscape structure analysis, patch index


r.li.cwed --help
r.li.cwed 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


r.li.cwed (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\r.li\output\ (MS-Windows) or $HOME/.grass7/r.li/output/ (GNU/Linux).

If the sample area contains only NULL values it is considered to have 0 patch and CWED=0. If Area is 0 r.li.cwed 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:

r.li.cwed input=my_map conf=my_conf output=my_out \

Example for input "weights.csv" file:


See Also

r.li - 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 (www.faunalia.it)
Markus Metz

Last changed: $Date: 2014-11-28 17:22:17 +0100 (Fri, 28 Nov 2014) $

Source Code

Available at: r.li.cwed source code (history)

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