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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)

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

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: 2014-12-24 15:11:14 +0100 (Wed, 24 Dec 2014) $

SOURCE CODE

       Available at: v.net.allpairs source code (history)

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