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 alayer=string nlayer=string [cats=range] [where=sql_query] [afcolumn=name] [abcolumn=name] [ncolumn=string] [--overwrite] [--verbose] [--quiet]
Flags:
- -g
- Use geodesic calculation for longitude-latitude locations
- --overwrite
- Allow output files to overwrite existing files
- --verbose
- Verbose module output
- --quiet
- Quiet module output
Parameters:
- input=name [required]
- Name of input vector map
- Or data source for direct OGR access
- output=name [required]
- Name for output vector map
- alayer=string [required]
- Layer number or name
- Arc layer
- Default: 1
- nlayer=string [required]
- Layer number or name
- Node layer
- 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 inhab >= 10000
- afcolumn=name
- Arc forward/both direction(s) cost column (number)
- abcolumn=name
- Arc backward direction cost column (number)
- ncolumn=string
- Node cost column (number)
DESCRIPTION
v.net.allpairs computes the shortest path between each selected
node and all other selected nodes.
NOTES
An attribute table is created and linked to layer 1. The table
contains three columns: cat, to_cat, cost.
Each entry denotes the cost of the shortest path from cat to
to_cat. If the cost is negative then no path exists. If points
are specified by cats, layer or where parameters then the
table is filled only for the selected points.
If abcolumn 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 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
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
Last changed: $Date: 2012-04-15 00:34:46 -0700 (Sun, 15 Apr 2012) $
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