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r.li.cwed

Calculates contrast weighted edge density index on a raster map

r.li.cwed input=name config=name path=name output=name [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

r.li.cwed input=name config=name path=name output=name

grass.script.run_command("r.li.cwed", input, config, path, output, overwrite=None, verbose=None, quiet=None, superquiet=None)

Example:

gs.run_command("r.li.cwed", input="name", config="name", path="name", output="name")

grass.tools.Tools.r_li_cwed(input, config, path, output, overwrite=None, verbose=None, quiet=None, superquiet=None)

Example:

tools = Tools()
tools.r_li_cwed(input="name", config="name", path="name", output="name")

This grass.tools API is experimental in version 8.5 and expected to be stable in version 8.6.

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
--overwrite
    Allow output files to overwrite existing files
--help
    Print usage summary
--verbose
    Verbose module output
--quiet
    Quiet module output
--qq
    Very quiet module output
--ui
    Force launching GUI dialog

input : str, required
    Name of input raster map
    Used as: input, raster, name
config : str, required
    Configuration file
    Used as: input, file, name
path : str, required
    Name of file that contains the weight to calculate the index
    Used as: input, file, name
output : str, required
    Name for output raster map
    Used as: output, raster, name
overwrite : bool, optional
    Allow output files to overwrite existing files
    Default: None
verbose : bool, optional
    Verbose module output
    Default: None
quiet : bool, optional
    Quiet module output
    Default: None
superquiet : bool, optional
    Very quiet module output
    Default: None

input : str | np.ndarray, required
    Name of input raster map
    Used as: input, raster, name
config : str | io.StringIO, required
    Configuration file
    Used as: input, file, name
path : str | io.StringIO, required
    Name of file that contains the weight to calculate the index
    Used as: input, file, name
output : str | type(np.ndarray) | type(np.array) | type(gs.array.array), required
    Name for output raster map
    Used as: output, raster, name
overwrite : bool, optional
    Allow output files to overwrite existing files
    Default: None
verbose : bool, optional
    Verbose module output
    Default: None
quiet : bool, optional
    Quiet module output
    Default: None
superquiet : bool, optional
    Very quiet module output
    Default: None

Returns:

result : grass.tools.support.ToolResult | np.ndarray | tuple[np.ndarray] | None
If the tool produces text as standard output, a ToolResult object will be returned. Otherwise, None will be returned. If an array type (e.g., np.ndarray) is used for one of the raster outputs, the result will be an array and will have the shape corresponding to the computational region. If an array type is used for more than one raster output, the result will be a tuple of arrays.

Raises:

grass.tools.ToolError: When the tool ended with an error.

DESCRIPTION

r.li.cwed (contrast weighted edge density) calculates the edge density between patch types specified:

rlicwed formula

with:

  • k: attribute
  • m: number of non-null attributes in the sampling area
  • e_ik: total length of edge in landscape between patch types i and k
  • d_ik: 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 ()
Markus Metz

SOURCE CODE

Available at: r.li.cwed source code (history)
Latest change: Tuesday Apr 29 06:19:47 2025 in commit 12f893b