1v.net.centrality(1)         GRASS GIS User's Manual        v.net.centrality(1)
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NAME

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

10       vector, network, centrality measures
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SYNOPSIS

13       v.net.centrality
14       v.net.centrality --help
15       v.net.centrality       [-ga]       input=name        [arc_layer=string]
16       [node_layer=string]    output=name    [cats=range]    [where=sql_query]
17       [arc_column=name]    [arc_backward_column=name]    [node_column=string]
18       [degree=name]     [closeness=name]     [betweenness=name]    [eigenvec‐
19       tor=name]     [iterations=integer]     [error=float]      [--overwrite]
20       [--help]  [--verbose]  [--quiet]  [--ui]
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22   Flags:
23       -g
24           Use geodesic calculation for longitude-latitude locations
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26       -a
27           Add points on nodes
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29       --overwrite
30           Allow output files to overwrite existing files
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32       --help
33           Print usage summary
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35       --verbose
36           Verbose module output
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38       --quiet
39           Quiet module output
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41       --ui
42           Force launching GUI dialog
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44   Parameters:
45       input=name [required]
46           Name of input vector map
47           Or data source for direct OGR access
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49       arc_layer=string
50           Arc layer
51           Vector  features can have category values in different layers. This
52           number determines which layer to use. When  used  with  direct  OGR
53           access this is the layer name.
54           Default: 1
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56       node_layer=string
57           Node layer
58           Vector  features can have category values in different layers. This
59           number determines which layer to use. When  used  with  direct  OGR
60           access this is the layer name.
61           Default: 2
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63       output=name [required]
64           Name for output vector map
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66       cats=range
67           Category values
68           Example: 1,3,7-9,13
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70       where=sql_query
71           WHERE conditions of SQL statement without ’where’ keyword
72           Example: income < 1000 and population >= 10000
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74       arc_column=name
75           Arc forward/both direction(s) cost column (number)
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77       arc_backward_column=name
78           Arc backward direction cost column (number)
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80       node_column=string
81           Node cost column (number)
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83       degree=name
84           Name of degree centrality column
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86       closeness=name
87           Name of closeness centrality column
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89       betweenness=name
90           Name of betweenness centrality column
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92       eigenvector=name
93           Name of eigenvector centrality column
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95       iterations=integer
96           Maximum number of iterations to compute eigenvector centrality
97           Default: 1000
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99       error=float
100           Cumulative error tolerance for eigenvector centrality
101           Default: 0.1
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DESCRIPTION

104       v.net.centrality  computes degree, closeness, betweenness and eigenvec‐
105       tor centrality measures.
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NOTES

108       The module computes various  centrality  measures  for  each  node  and
109       stores  them  in the given columns of an attribute table, which is cre‐
110       ated and linked to the output map. For the description of these, please
111       check the following wikipedia article.  If the column name is not given
112       for a measure then that measure is not computed. If -a flag is set then
113       points  are  added  on nodes without points. Also, the points for which
114       the output is computed can be specified by cats, layer and where param‐
115       eters.  However,  if any of these parameters is present then -a flag is
116       ignored and no new points are added.
117       Betweenness measure is not normalised. In order to get  the  normalised
118       values  (between  0 and 1), each number needs to be divided by N choose
119       2=N*(N-1)/2 where N is the number of nodes in the connected  component.
120       Computation  of  eigenvector  measure terminates if the given number of
121       iterations is reached or the cumulative squared error between the  suc‐
122       cessive iterations is less than error.
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EXAMPLES

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

132        v.net, v.generalize
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AUTHORS

135       Daniel Bundala, Google Summer of Code 2009, Student
136       Wolf Bergenheim, Mentor
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SOURCE CODE

139       Available at: v.net.centrality source code (history)
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141       Main  index  | Vector index | Topics index | Keywords index | Graphical
142       index | Full index
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144       © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
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148GRASS 7.8.5                                                v.net.centrality(1)