.TH v.net.spanningtree 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBv.net.spanningtree\fR\fR  \- Computes minimum spanning tree for the network.
.SH KEYWORDS
vector, network, spanning tree
.SH SYNOPSIS
\fBv.net.spanningtree\fR
.br
\fBv.net.spanningtree \-\-help\fR
.br
\fBv.net.spanningtree\fR [\-\fBg\fR] \fBinput\fR=\fIname\fR \fBoutput\fR=\fIname\fR  [\fBarc_layer\fR=\fIstring\fR]   [\fBnode_layer\fR=\fIstring\fR]   [\fBarc_column\fR=\fIname\fR]   [\fBnode_column\fR=\fIname\fR]   [\-\-\fBoverwrite\fR]  [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-g\fR" 4m
.br
Use geodesic calculation for longitude\-latitude locations
.IP "\fB\-\-overwrite\fR" 4m
.br
Allow output files to overwrite existing files
.IP "\fB\-\-help\fR" 4m
.br
Print usage summary
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.IP "\fB\-\-ui\fR" 4m
.br
Force launching GUI dialog
.SS Parameters:
.IP "\fBinput\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of input vector map
.br
Or data source for direct OGR access
.IP "\fBoutput\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name for output vector map
.IP "\fBarc_layer\fR=\fIstring\fR" 4m
.br
Arc layer
.br
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.
.br
Default: \fI1\fR
.IP "\fBnode_layer\fR=\fIstring\fR" 4m
.br
Node layer
.br
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.
.br
Default: \fI2\fR
.IP "\fBarc_column\fR=\fIname\fR" 4m
.br
Arc forward/both direction(s) cost column (number)
.IP "\fBnode_column\fR=\fIname\fR" 4m
.br
Node cost column (number)
.SH DESCRIPTION
\fIv.net.spanningtree\fR finds the minimum spanning tree in a
network.
.SH 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,
\fIv.net.spanningtree\fR 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. \fBAccol\fR is used to specify the
costs of the edges. The \fBoutput\fR consists of the edges in the
spanning tree.
.SH EXAMPLES
Find cheapest set of pipelines connecting all nodes.
.br
.nf
\fC
v.net.spanningtree input=projected_pipelines output=spanningtree accol=cost
\fR
.fi
.SH SEE ALSO
\fI
v.net,
v.net.steiner
\fR
.SH AUTHORS
Daniel Bundala, Google Summer of Code 2009, Student
.br
Wolf Bergenheim, Mentor
.SH SOURCE CODE
.PP
Available at: v.net.spanningtree source code (history)
.PP
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.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual