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v.net.spanningtree(1grass)


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 an
   undirected network (same forward and backward costs). 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: 2016-03-08 22:04:56 +0100 (Tue, 08 Mar 2016) $

SOURCE CODE

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

   Main  index  | Vector index | Topics index | Keywords index | Graphical
   index | Full index

    2003-2016 GRASS Development Team, GRASS GIS 7.2.0 Reference Manual



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