Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.
NAME
r.pi.graph  - Graph Theory for connectivity analysis.
KEYWORDS
raster, 
landscape structure analysis, 
connectivity analysis
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
 
 
Graph Theory for connectivity analysis.
...
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.
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
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: Tuesday Sep 19 09:59:22 2023 in commit: e76c325998c8cd9053ce012a5adbb79f33ab0779
Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.
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© 2003-2023
GRASS Development Team,
GRASS GIS 8.2.2dev Reference Manual