v.net.allpairs(1grass) GRASS GIS User's Manual v.net.allpairs(1grass)
NAME
v.net.allpairs - Computes the shortest path between all pairs of nodes
in the network.
KEYWORDS
vector, network, shortest path
SYNOPSIS
v.net.allpairs
v.net.allpairs --help
v.net.allpairs [-g] input=name output=name [arc_layer=string]
[node_layer=string] [cats=range] [where=sql_query] [arc_col-
umn=name] [arc_backward_column=name] [node_column=string]
[--overwrite] [--help] [--verbose] [--quiet] [--ui]
Flags:
-g
Use geodesic calculation for longitude-latitude locations
--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 vector map
Or data source for direct OGR access
output=name [required]
Name for output vector map
arc_layer=string
Arc layer
Vector features can have category values in different layers. This
number determines which layer to use. When used with direct OGR ac-
cess this is the layer name.
Default: 1
node_layer=string
Node layer
Vector features can have category values in different layers. This
number determines which layer to use. When used with direct OGR ac-
cess this is the layer name.
Default: 2
cats=range
Category values
Example: 1,3,7-9,13
where=sql_query
WHERE conditions of SQL statement without ’where’ keyword
Example: income < 1000 and population >= 10000
arc_column=name
Arc forward/both direction(s) cost column (number)
arc_backward_column=name
Arc backward direction cost column (number)
node_column=string
Node cost column (number)
DESCRIPTION
v.net.allpairs computes the shortest path between each selected node
and all other selected nodes. The output is a vector with the selected
nodes and the shortest paths.
NOTES
An attribute table is created and linked to layer arc_layer. The table
contains four columns: cat, from_cat, to_cat, cost. Each cat entry de-
notes the category of the shortest path from the node with category
from_cat to the node with category to_cat. If points are specified by
cats, layer or where parameters then the table is filled only for the
selected points.
If arc_backward_column is not given then then the same costs are used
for forward and backward arcs.
EXAMPLE
Find shortest path along roads from selected archsites (Spearfish sam-
ple dataset):
# prepare network: connect archsites to roads with threshold 200
v.net input=roads@PERMANENT points=archsites@PERMANENT \
output=roads_net operation=connect thresh=200
# verify result
v.category input=roads_net option=report
# only lines should have a category in layer 1
# only points should have a category in layer 2
# shortest path between all points with categories 1 - 5 in layer 2
v.net.allpairs input=roads_net cats=1-5 out=roads_net_all
v.db.select roads_net_all
Result in matrix form:
from\to 1 3 4 5
1 0 18820.386 17206.651 17373.274
3 18820.386 0 1739.079 9040.575
4 17206.651 1739.079 0 7426.84
5 17373.274 9040.575 7426.84 0
SEE ALSO
v.net.path, v.net.distance
AUTHORS
Daniel Bundala, Google Summer of Code 2009, Student
Wolf Bergenheim, Mentor
Markus Metz
SOURCE CODE
Available at: v.net.allpairs source code (history)
Accessed: unknown
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GRASS 7.8.7 v.net.allpairs(1grass)
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