.TH v.import 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBv.import\fR\fR  \- Imports vector data into a GRASS vector map using OGR library and reprojects on the fly.
.SH KEYWORDS
vector, import, projection
.SH SYNOPSIS
\fBv.import\fR
.br
\fBv.import \-\-help\fR
.br
\fBv.import\fR [\-\fBflo\fR] \fBinput\fR=\fIstring\fR  [\fBlayer\fR=\fIstring\fR[,\fIstring\fR,...]]   [\fBoutput\fR=\fIname\fR]   [\fBextent\fR=\fIstring\fR]   [\fBencoding\fR=\fIstring\fR]   [\fBsnap\fR=\fIfloat\fR]   [\fBepsg\fR=\fIinteger\fR]   [\fBdatum_trans\fR=\fIinteger\fR]   [\-\-\fBoverwrite\fR]  [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-f\fR" 4m
.br
List supported OGR formats and exit
.IP "\fB\-l\fR" 4m
.br
List available OGR layers in data source and exit
.IP "\fB\-o\fR" 4m
.br
Override projection check (use current location\(cqs projection)
.br
Assume that the dataset has the same projection as the current location
.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=\fIstring\fR \fB[required]\fR" 4m
.br
Name of OGR datasource to be imported
.IP "\fBlayer\fR=\fIstring[,\fIstring\fR,...]\fR" 4m
.br
OGR layer name. If not given, all available layers are imported
.IP "\fBoutput\fR=\fIname\fR" 4m
.br
Name for output vector map (default: input)
.IP "\fBextent\fR=\fIstring\fR" 4m
.br
Output vector map extent
.br
Options: \fIinput, region\fR
.br
Default: \fIinput\fR
.br
\fBinput\fR: extent of input map
.br
\fBregion\fR: extent of current region
.IP "\fBencoding\fR=\fIstring\fR" 4m
.br
Encoding value for attribute data
.IP "\fBsnap\fR=\fIfloat\fR" 4m
.br
Snapping threshold for boundaries (map units)
.br
A suitable threshold is estimated during import
.br
Default: \fI\-1\fR
.IP "\fBepsg\fR=\fIinteger\fR" 4m
.br
EPSG projection code
.br
Options: \fI1\-1000000\fR
.IP "\fBdatum_trans\fR=\fIinteger\fR" 4m
.br
Index number of datum transform parameters
.br
\-1 to list available datum transform parameters
.br
Options: \fI\-1\-100\fR
.SH DESCRIPTION
\fIv.import\fR imports vector data from files and database connections
supported by the OGR library) into the
current location and mapset. If the projection of the input
does not match the projection of the location, the input is reprojected
into the current location. In case that the projection of the input map
does match the projection of the location, the input is imported directly.
.SS Supported Vector Formats
\fIv.import\fR uses the OGR library which supports various vector data
formats including ESRI
Shapefile, Mapinfo
File, UK .NTF, SDTS, TIGER, IHO S\-57 (ENC), DGN, GML, GPX, AVCBin, REC,
Memory, OGDI, and PostgreSQL, depending on the local OGR installation.
For details see the OGR web
site. The OGR (Simple Features Library) is part of the
GDAL library, hence GDAL needs to be
installed to use \fIv.in.ogr\fR.
.PP
The list of actually supported formats can be printed by \fB\-f\fR flag.
.SH NOTES
\fIv.import\fR checks the projection metadata of the dataset to be
imported against the current location\(cqs projection. If not identical a
related error message is shown.
.br
To override this projection check (i.e. to use current location\(cqs projection)
by assuming that the dataset has the same projection as the current location
the \fB\-o\fR flag can be used. This is also useful when geodata to be
imported do not contain any projection metadata at all. The user must be
sure that the projection is identical in order to avoid to introduce data
errors.
.SS Topology cleaning
When importing polygons, non\-topological polygons are converted to
topological areas. If the input polygons contain errors (unexpected
overlapping areas, small gaps between polygons, or warnings about being
unable to calculate centroids), the import might need to be repeated
using a \fIsnap\fR value as suggested in the output messages. The
default value of snap=\-1 means that no snapping will be done.
.PP
The \fIsnap\fR threshold defines the maximal distance from one to another
vertex in map units (for latitude\-longitude locations in degrees). If there
is no other vertex within \fIsnap\fR distance, no snapping will be done.
Note that a too large value can severely damage area topology, beyond repair.
.PP
\fIPost\-processing:\fR Snapped boundaries may need to be cleaned with
\fIv.clean\fR, using its tools \fIbreak,rmdupl,rmsa\fR. For details,
refer to the \fIv.clean\fR manual page.
.SH EXAMPLE
.br
.nf
\fC
# import SHAPE file at full extent and reproject to current location projection
v.import input=research_area.shp output=research_area extent=input
\fR
.fi
.SH ERROR MESSAGES
.SS SQL syntax errors
Depending on the currently selected SQL driver, error messages such as follows may arise:
.br
.nf
\fC
DBMI\-SQLite driver error:
Error in sqlite3_prepare():
near \(dqORDER\(dq: syntax error
\fR
.fi
Or:
.br
.nf
\fC
DBMI\-DBF driver error:
SQL parser error:
syntax error, unexpected DESC, expecting NAME processing \(cqDESC
\fR
.fi
This indicates that a column name in the input dataset corresponds to a reserved
SQL word (here: \(cqORDER\(cq and \(cqDESC\(cq respectively). A different column name has to be
used in this case. The \fBcolumns\fR parameter can be used to assign different
column names on the fly in order to avoid using reserved SQL words.
For a list of SQL reserved words for SQLite (the default driver),
see here.
.SS Projection errors
.br
.nf
\fC
Projection of dataset does not appear to match the current location.
\fR
.fi
Here you need to create or use a location whose projection matches that
of the vector data you wish to import. Try using \fBlocation\fR parameter to
create a new location based upon the projection information in the file. If
desired, you can then re\-project it to another location
with \fIv.proj\fR.
.SH SEE ALSO
\fI
v.clean,
v.in.lines,
v.in.ogr,
v.proj
\fR
.SH AUTHORS
Markus Metz
.br
Improvements: Martin Landa, Anna Petrasova
.SH SOURCE CODE
.PP
Available at: v.import source code (history)
.PP
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.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual