NAME

       v.net.spanningtree  - Computes minimum spanning tree for the network.

KEYWORDS

       vector, network, spanning tree

SYNOPSIS

       v.net.spanningtree
       v.net.spanningtree --help
       v.net.spanningtree  [-g]  input=name output=name  [arc_layer=string]   [node_layer=string]
       [arc_column=name]   [node_column=name]   [--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

       arc_column=name
           Arc forward/both direction(s) cost column (number)

       node_column=name
           Node cost column (number)

DESCRIPTION

       v.net.spanningtree finds the minimum spanning tree in a network.

NOTES

       A  spanning  tree is a minimum cost subnetwork connecting all nodes in a network. Or, if a
       network is disconnected then the module  computes  the  minimum  spanning  tree  for  each
       (weakly)  connected  component. So, strictly speaking, v.net.spanningtree does not compute
       spanning tree but a spanning forest. As the name suggests, a spanning tree is a tree. That
       is,  it  contains  no  cycles  and  if a component has N nodes then the tree has N-1 edges
       connecting all nodes. Accol is used to specify the costs of the edges. The output consists
       of the edges in the spanning tree.

EXAMPLES

       Find cheapest set of pipelines connecting all nodes.
       v.net.spanningtree input=projected_pipelines output=spanningtree accol=cost

SEE ALSO

        v.net, v.net.steiner

AUTHORS

       Daniel Bundala, Google Summer of Code 2009, Student
       Wolf Bergenheim, Mentor

       Last changed: $Date: 2013-05-23 21:59:24 +0200 (Thu, 23 May 2013) $

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