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
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_column=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 access 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 access 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)
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.
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 denotes 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.
Find shortest path along roads from selected archsites (Spearfish sample
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
v.net.path,
v.net.distance
Daniel Bundala, Google Summer of Code 2009, Student
Wolf Bergenheim, Mentor
Markus Metz
SOURCE CODE
Available at:
v.net.allpairs source code
(history)
Latest change: Mon Nov 18 20:15:32 2019 in commit: 1a1d107e4f6e1b846f9841c2c6fabf015c5f720d
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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GRASS Development Team,
GRASS GIS 7.8.8dev Reference Manual