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NAME

r.pi.graph - Graph Theory for connectivity analysis.

KEYWORDS

raster

SYNOPSIS

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

Flags:

-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
--ui
Force launching GUI dialog

Parameters:

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
Options: nearest_neighbor, relative_neighbor, gabriel, spanning_tree
index=string [required]
Cluster index
Options: 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

Table of contents

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.

SEE ALSO

r.pi.corearea, r.pi.corr.mw, r.pi.csr.mw, r.pi.export, r.pi.graph.dec, r.pi.graph.pr, r.pi.graph.red, r.pi.grow, r.pi.import, r.pi.index, r.pi.lm, r.pi.odc, r.pi.prob.mw, r.pi.rectangle, r.pi

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: Wed Feb 2 21:46:15 2022 in commit: 2e3dcb5eafe36d640aa68585be0192f07ca1eabb

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© 2003-2022 GRASS Development Team, GRASS GIS 8.0.3dev Reference Manual