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NAME  - Computes strongly and weakly connected components in the network.


       vector, network, components

SYNOPSIS help    [-a]    input=name     [layer=integer]     output=name   method=string
       [--overwrite]  [--verbose]  [--quiet]

           Add points on nodes

           Allow output files to overwrite existing files

           Verbose module output

           Quiet module output

           Name of input vector map

           Layer number
           A single vector map  can  be  connected  to  multiple  database  tables.  This  number
           determines which table to use.
           Default: 1

           Name for output vector map

           Type of components
           Options: weak,strong
           weak: Weakly connected components
           strong: Strongly connected components

DESCRIPTION computes the weakly and strongly connected components in a network.


       Two  nodes,  u  and  v  are in the same strongly connected component if there are directed
       paths from u to v and from v to u. The nodes are in the same  weakly  connected  component
       if, ignoring orientation of the edges, there is a path between them.
       The type of components is specified by method parameter. creates a table
       and links it to the given layer.  This table contains only two integer  columns:  cat  and
       comp  .  If  a  point  or  both  endpoints of a line belong to the same component then the
       point/line is written to the output map and  appropriate  information  is  stored  in  the
       table.  If  -a  flag  is  set then new points are added on the nodes without points. These
       points have category numbers larger than any category used in the input map.


       Any road network should form a single strongly  connected  component.   Otherwise,  it  is
       impossible to travel between some places. input=roads output=roads_components method=strong

SEE ALSO, v.category,


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

       Last changed: $Date: 2013-05-23 13:01:55 -0700 (Thu, 23 May 2013) $

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