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NAME

       v.import   -  Imports vector data into a GRASS vector map using OGR library and reprojects
       on the fly.

KEYWORDS

       vector, import, projection

SYNOPSIS

       v.import
       v.import --help
       v.import     [-flo]     input=string      [layer=string[,string,...]]        [output=name]
       [extent=string]           [encoding=string]           [snap=float]          [epsg=integer]
       [datum_trans=integer]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -f
           List supported OGR formats and exit

       -l
           List available OGR layers in data source and exit

       -o
           Override projection check (use current location’s projection)
           Assume that the dataset has the same projection as the current location

       --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=string [required]
           Name of OGR datasource to be imported

       layer=string[,string,...]
           OGR layer name. If not given, all available layers are imported

       output=name
           Name for output vector map (default: input)

       extent=string
           Output vector map extent
           Options: input, region
           Default: input
           input: extent of input map
           region: extent of current region

       encoding=string
           Encoding value for attribute data

       snap=float
           Snapping threshold for boundaries (map units)
           A suitable threshold is estimated during import
           Default: -1

       epsg=integer
           EPSG projection code
           Options: 1-1000000

       datum_trans=integer
           Index number of datum transform parameters
           -1 to list available datum transform parameters
           Options: -1-100

DESCRIPTION

       v.import 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.

   Supported Vector Formats
       v.import 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 v.in.ogr.

       The list of actually supported formats can be printed by -f flag.

NOTES

       v.import checks the projection metadata of the dataset to be imported against the  current
       location’s projection. If not identical a related error message is shown.
       To  override this projection check (i.e. to use current location’s projection) by assuming
       that the dataset has the same projection as the current location the -o 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.

   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 snap value as suggested in the output messages.

       The snap threshold defines the maximal distance from one to another vertex  in  map  units
       (for  latitude-longitude  locations  in  degree).  If there is no other vertex within snap
       distance, no snapping will be done.  Note that a too large value can severely damage  area
       topology, beyond repair.

       Post-processing:  Snapped  boundaries may need to be cleaned with v.clean, using its tools
       break,rmdupl,rmsa. For details, refer to the v.clean manual page.

EXAMPLE

       # import SHAPE file at full extent and reproject to current location projection
       v.import input=research_area.shp output=research_area extent=input

ERROR MESSAGES

   SQL syntax errors
       Depending on the currently selected SQL driver, error messages such as follows may arise:
       DBMI-SQLite driver error:
       Error in sqlite3_prepare():
       near "ORDER": syntax error
       Or:
       DBMI-DBF driver error:
       SQL parser error:
       syntax error, unexpected DESC, expecting NAME processing ’DESC
       This indicates that a column name in the input dataset corresponds to a reserved SQL  word
       (here:  ’ORDER’  and  ’DESC’ respectively). A different column name has to be used in this
       case. The columns 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.

   Projection errors
       Projection of dataset does not appear to match the current location.
       Here you need to create or use a location whose projection matches that of the vector data
       you  wish  to import. Try using location 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 v.proj.

SEE ALSO

        v.clean, v.in.ogr, v.proj

AUTHORS

       Markus Metz
       Improvements: Martin Landa, Anna Petrasova

       Last changed: $Date: 2018-10-14 13:08:03 +0200 (Sun, 14 Oct 2018) $

SOURCE CODE

       Available at: v.import source code (history)

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       © 2003-2019 GRASS Development Team, GRASS GIS 7.6.1 Reference Manual