NAME

       v.net.centrality   -  Computes  degree,  centrality,  betweeness,  closeness  and  eigenvector centrality
       measures in the network.

KEYWORDS

       vector, network, centrality measures

SYNOPSIS

       v.net.centrality
       v.net.centrality --help
       v.net.centrality [-ga] input=name  [arc_layer=string]    [node_layer=string]   output=name   [cats=range]
       [where=sql_query]   [arc_column=name]   [arc_backward_column=name]   [node_column=string]   [degree=name]
       [closeness=name]     [betweenness=name]     [eigenvector=name]     [iterations=integer]     [error=float]
       [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -g
           Use geodesic calculation for longitude-latitude locations

       -a
           Add points on nodes

       --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

       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

       output=name [required]
           Name for output vector map

       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)

       degree=name
           Name of degree centrality column

       closeness=name
           Name of closeness centrality column

       betweenness=name
           Name of betweenness centrality column

       eigenvector=name
           Name of eigenvector centrality column

       iterations=integer
           Maximum number of iterations to compute eigenvector centrality
           Default: 1000

       error=float
           Cumulative error tolerance for eigenvector centrality
           Default: 0.1

DESCRIPTION

       v.net.centrality computes degree, closeness, betweenness and eigenvector centrality measures.

NOTES

       The module computes various centrality measures for each node and stores them in the given columns of  an
       attribute  table,  which  is  created  and linked to the output map. For the description of these, please
       check the following wikipedia article.  If the column name is not given for a measure then  that  measure
       is  not  computed.  If -a flag is set then points are added on nodes without points. Also, the points for
       which the output is computed can be specified by cats, layer and where parameters.  However,  if  any  of
       these parameters is present then -a flag is ignored and no new points are added.
       Betweenness  measure  is  not  normalised.  In order to get the normalised values (between 0 and 1), each
       number needs to be divided by N choose 2=N*(N-1)/2 where N is  the  number  of  nodes  in  the  connected
       component.  Computation of eigenvector measure terminates if the given number of iterations is reached or
       the cumulative squared error between the successive iterations is less than error.

EXAMPLES

       Compute closeness and betweenness centrality measures for each node and produce a map containing not only
       points already present in the input map but a map with point on every node.
       v.net.centrality input=roads output=roads_cent closeness=closeness \
             betweenness=betweenness -a

SEE ALSO

        v.net, v.generalize

AUTHORS

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

SOURCE CODE

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

       Accessed: Monday Apr 01 03:08:45 2024

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

       © 2003-2024 GRASS Development Team, GRASS GIS 8.3.2 Reference Manual

GRASS 8.3.2                                                                             v.net.centrality(1grass)