r.pi.graph

Graph Theory for connectivity analysis.

Command linePython (grass.script)

r.pi.graph [-a] input=name output=string keyval=integer distance=float neighborhood=string index=string [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

r.pi.graph input=name output=string keyval=integer distance=float neighborhood=string index=string

grass.script.run_command("r.pi.graph", input, output, keyval, distance, neighborhood, index, flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("r.pi.graph", input="name", output="string", keyval=integer, distance=float, neighborhood="string", index="string")

Parameters

Command linePython (grass.script)

input=name [required]
    Name of input raster map
output=string [required]
    Name of the new raster file
keyval=integer [required]
    Key value
distance=float [required]
    Bounding distance [0 for maximum distance]
neighborhood=string [required]
    Neighborhood definition
    Allowed values: nearest_neighbor, relative_neighbor, gabriel, spanning_tree
index=string [required]
    Cluster index
    Allowed values: connectance_index, gyration_radius, cohesion_index, percent_patches, percent_area, number_patches, number_links, mean_patch_size, largest_patch_size, largest_patch_diameter, graph_diameter
-a
    Set for 8 cell-neighbors. 4 cell-neighbors are default
--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
output : str, required
    Name of the new raster file
    Used as: output, raster
keyval : int, required
    Key value
distance : float, required
    Bounding distance [0 for maximum distance]
neighborhood : str, required
    Neighborhood definition
    Allowed values: nearest_neighbor, relative_neighbor, gabriel, spanning_tree
index : str, required
    Cluster index
    Allowed values: connectance_index, gyration_radius, cohesion_index, percent_patches, percent_area, number_patches, number_links, mean_patch_size, largest_patch_size, largest_patch_diameter, graph_diameter
flags : str, optional
    Allowed values: a
    a
        Set for 8 cell-neighbors. 4 cell-neighbors are default
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

Graph Theory for connectivity analysis.

NOTES

...

EXAMPLE

An example for the North Carolina sample dataset using class 5 (forest): Computing a graph of all patches (4 neighbourhood rule) using a maximum distance of 10 pixel, the Gabriel method and as resulting index the largest patch diameter:

r.pi.graph input=landclass96 output=landclass96_graph keyval=5 distance=10 neighborhood=gabriel index=largest_patch_diameter

the results are 2 files:
landclass96_graph: the information of the index are provided (here a range of 3-589 of patch diameter)
landclass96_graph_clusters: the generated cluster IDs are provided (here 16 clusters are identified), doing it with a distance of 5 pixel is resulting in a total of 66 clusters.

AUTHORS

Programming: Elshad Shirinov
Scientific concept: Dr. Martin Wegmann
Department of Remote Sensing
Remote Sensing and Biodiversity Unit
University of Wuerzburg, Germany

Port to GRASS GIS 7: Markus Metz

SOURCE CODE

Available at: r.pi.graph source code (history)
Latest change: Thursday Feb 20 13:02:26 2025 in commit 53de819