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r.li.edgedensity

Calculates edge density index on a raster map, using a 4 neighbour algorithm

r.li.edgedensity [-b] input=name config=name output=name [patch_type=string] [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

r.li.edgedensity input=name config=name output=name

grass.script.run_command("r.li.edgedensity", input, config, output, patch_type=None, flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

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

Parameters

input=name [required]
    Name of input raster map
config=name [required]
    Configuration file
output=name [required]
    Name for output raster map
patch_type=string
    The value of the patch type
    It can be integer, double or float; it will be changed in function of map type
-b
    Exclude border edges
--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
output : str, required
    Name for output raster map
    Used as: output, raster, name
patch_type : str, optional
    The value of the patch type
    It can be integer, double or float; it will be changed in function of map type
flags : str, optional
    Allowed values: b
    b
        Exclude border edges
overwrite: bool, optional
    Allow output files to overwrite existing files
    Default: False
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

DESCRIPTION

r.li.edgedensity calculates:

  • the density of all edges of patch type k r.li.edgedensity formula
  1 , or
  • the density of all edges in the sampling area if k is not specified, r.li.edgedensity formula 2

with:

  • k: patch type
  • m: number of patch types
  • n: number of edge segments of patch type k
  • e_ik :total edge length in the landscape involving patch type k
  • Area: total landscape area

The unit is meters per hectare.

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 input raster map contains only NULL values then r.li.edgedensity consider to have 0 patches.
If area is 0 r.li.edgedensity returns NULL; this is only possible if input raster is masked.

EXAMPLES

To calculate the 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.edgedensity input=my_map conf=my_conf output=my_out

To calculate edge density index of patch_type 34, using "my_conf" configuration file and on map "my_map", saving results in "my_out" file run:

r.li.edgedensity input=my_map conf=my_conf output=my_out patch_type=34

Forest map (Spearfish sample dataset) example:

g.region raster=landcover.30m -p
r.mapcalc "forests = if(landcover.30m >= 41 && landcover.30m <= 43,1,null())"
r.li.edgedensity input=forests conf=movwindow7 out=forests_edgedens_mov7
r.univar forests_edgedens_mov7

Forest map (North Carolina sample dataset) example:

g.region raster=landclass96 -p
r.mapcalc "forests = if(landclass96 == 5, 1, null() )"
r.li.edgedensity input=forests conf=movwindow7 out=forests_edgedensity_mov7

# verify
r.univar forests_edgedensity_mov7
r.to.vect input=forests output=forests type=area
d.mon wx0
d.rast forests_edgedensity_mov7
d.vect forests type=boundary

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.edgedensity source code (history)
Latest change: Wednesday Feb 19 22:09:55 2025 in commit 5f4fa06