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 alayer. 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 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
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
Last changed: $Date: 2012-10-13 11:00:14 +0200 (Sat, 13 Oct 2012) $