r.li.cwed(1)

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

  Flags:

--overwrite
    Allow output files to overwrite existing files

--help
    Print usage summary

--verbose
    Verbose module output

--quiet
    Quiet module output

--ui
    Force launching GUI dialog

  Parameters:

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

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 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:
patchType1,patchType2,dissimilarityBetweenPatchType1andPatchType2

NOTES
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\GRASS8\r.li\output\ (MS-Windows) or $HOME/.grass8/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.

EXAMPLES
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 \
          path=/path/to/weights.csv

Example for input "weights.csv" file:

12,16,0.65
44,123,0.32
56,12,0.54
23,66,0.99

SEE ALSO
r.li - package overview, g.gui.rlisetup

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. (PDF)

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

SOURCE CODE

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

Accessed: Saturday May 09 11:15:49 2026

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