v.net.allpairsgrass - Online in the Cloud

PROGRAM:

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 inhab >= 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 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.

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

Use v.net.allpairsgrass online using onworks.net services