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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=None, verbose=None, quiet=None, superquiet=None)

Example:

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

grass.tools.Tools.r_li_edgedensity(input, config, output, patch_type=None, flags=None, overwrite=None, verbose=None, quiet=None, superquiet=None)

Example:

tools = Tools()
tools.r_li_edgedensity(input="name", config="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
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: 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
output : str | type(np.ndarray) | type(np.array) | type(gs.array.array), 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: 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.

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 Apr 30 17:57:46 2025 in commit 633b026