.TH v.build 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBv.build\fR\fR  \- Creates topology for vector map.
.br
Optionally also checks for topological errors.
.SH KEYWORDS
vector, topology, geometry
.SH SYNOPSIS
\fBv.build\fR
.br
\fBv.build \-\-help\fR
.br
\fBv.build\fR [\-\fBe\fR] \fBmap\fR=\fIname\fR  [\fBerror\fR=\fIname\fR]  \fBoption\fR=\fIstring\fR[,\fIstring\fR,...]  [\-\-\fBoverwrite\fR]  [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-e\fR" 4m
.br
Extensive checks for topological errors
.br
Perform in\-depth checks for topological errors when building topology
.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 "\fBmap\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of vector map
.IP "\fBerror\fR=\fIname\fR" 4m
.br
Name for output vector map where erroneous vector features are written to
.IP "\fBoption\fR=\fIstring[,\fIstring\fR,...]\fR \fB[required]\fR" 4m
.br
Build topology or dump topology or indices to standard output
.br
Options: \fIbuild, dump, sdump, cdump, fdump\fR
.br
Default: \fIbuild\fR
.br
\fBbuild\fR: build topology
.br
\fBdump\fR: write topology to stdout
.br
\fBsdump\fR: write spatial index to stdout
.br
\fBcdump\fR: write category index to stdout
.br
\fBfdump\fR: write feature index to stdout (OGR simple\-feature\-based formats only)
.SH DESCRIPTION
\fIv.build\fR builds support files for GRASS vector maps. These
support files supply topology and category information including
spatial index that are needed by other GRASS modules.
.PP
GRASS is generating these support files automatically, only in rare
cases the user has to (re)build them.
.PP
Refer to
vector data processing in GRASS GIS for
more information on GRASS vector data model.
.SH NOTES
\fIv.build\fR creates support files only for vector maps located in
the user\(cqs current mapset. It\(cqs not possible to rebuild support files
(\fBoption=build\fR) for vector maps from other mapsets.
.PP
In case of errors, the user can optionally generate an \fBerror\fR
vector map containing the erroneous vectors for later inspection.
.PP
If \fBerror\fR vector map is specified, \fIv.build\fR checks:
.RS 4n
.IP \(bu 4n
isolated bondaries (which are not forming any areas),
.IP \(bu 4n
centroids outside of area,
.IP \(bu 4n
duplicated centroids.
.RE
.PP
Extensive checks for topological errors (flag \fB\-e\fR) also
includes:
.RS 4n
.IP \(bu 4n
lines or boundaries of zero length,
.IP \(bu 4n
intersecting boundaries, ie. overlapping areas,
.IP \(bu 4n
areas without centroids that are not isles.
.RE
.SH EXAMPLES
.SS Build topology
Note that \fBoption=build\fR recreates also spatial and category
indices, not only topology. For linked OGR layers
(see \fIv.external\fR) also feature
index is created.
.br
.nf
\fC
v.build map=urbanarea option=build
\fR
.fi
Note that the vector map \fIurbanarea\fR must be located in the
current mapset.
.SS Dump topology or indices
Dump options print topology, spatial, category or feature index to
standard output. Such information can be printed also for vector maps
from other mapsets. A description of the vector topology is available in
the GRASS GIS 7 Programmer\(cqs Manual,
section \(dqVector library topology management\(dq.
.br
.nf
\fC
v.build map=urbanarea option=dump
\fR
.fi
.SH SEE ALSO
\fI
v.build.all,
v.build.polylines,
v.edit,
v.split
\fR
.PP
See also \fIwxGUI vector digitizer\fR.
.SH AUTHORS
Dave Gerdes, U.S.Army Construction Engineering Research
Laboratory,
.br
Michael Higgins, U.S.Army Construction Engineering Research Laboratory,
.br
Radim Blazek, ITC\-irst, Trento, Italy
.SH SOURCE CODE
.PP
Available at: v.build source code (history)
.PP
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.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual