NAME

       v.external  - Creates a new vector as a read-only link to OGR layer.
       Available            drivers:           ESRI           Shapefile,MapInfo           File,UK
       .NTF,SDTS,TIGER,S57,DGN,VRT,REC,Memory,BNA,CSV,NAS,GML,GPX,LIBKML,KML,GeoJSON,Interlis
       1,Interlis
       2,GMT,SQLite,DODS,ODBC,PGeo,MSSQLSpatial,OGDI,PostgreSQL,MySQL,PCIDSK,XPlane,AVCBin,AVCE00,DXF,Geoconcept,GeoRSS,GPSTrackMaker,VFK,PGDump,OSM,GPSBabel,SUA,OpenAir,PDS,WFS,HTF,AeronavFAA,Geomedia,EDIGEO,GFT,SVG,CouchDB,Idrisi,ARCGEN,SEGUKOOA,SEGY,XLS,ODS,XLSX,ElasticSearch,PDF

KEYWORDS

       vector, external, import

SYNOPSIS

       v.external
       v.external help
       v.external   dsn=string    [output=name]     [layer=string]    [--overwrite]   [--verbose]
       [--quiet]

   Flags:
       --overwrite
           Allow output files to overwrite existing files

       --verbose
           Verbose module output

       --quiet
           Quiet module output

   Parameters:
       dsn=string
           OGR datasource name. Examples:
                     ESRI  Shapefile:  directory   containing   shapefiles        MapInfo   File:
           directory containing mapinfo files

       output=name
           Output vector. If not given, available layers are printed only.

       layer=string
           OGR layer name. If not given, available layers are printed only. Examples:
                     ESRI Shapefile: shapefile name          MapInfo File: mapinfo file name

DESCRIPTION

       v.external  creates  new  vector as a link to external OGR layer (read only).  OGR (Simple
       Features Library) is part of the GDAL  library,  so  you  need  to  install  GDAL  to  use
       v.external and external OGR layers.

   Supported OGR Vector Formats
       ESRI Shapefile
       Mapinfo File

       Further  available drivers such as UK .NTF, SDTS, TIGER, IHO S-57 (ENC), DGN, GML, AVCBin,
       REC, Memory, OGDI, and PostgreSQL depend on the  local  installation  (OGR  library),  for
       details see OGR web site.

EXAMPLES

       SHAPE files

       v.external dsn=/home/user/shape_data layer=test_shape output=grass_map

       MapInfo files

       v.external dsn=./ layer=mapinfo_test output=grass_map

       SDTS files (you have to select the CATD file)

       v.external dsn=CITXCATD.DDF output=cities

       TIGER files

       v.external dsn=input/2000/56015/ layer=CompleteChain,PIP output=t56015_all

       PostGIS maps (area example)

       v.external dsn="PG:host=localhost user=postgres dbname=postgis" layer=polymap \
       output=polygons

NOTES

       The  simple  feature  data model used by OGR is very different from the topological format
       used by GRASS. Instead of true topology, so called 'pseudo topology' is created  for  data
       linked  by v.external.  User should learn the difference between those to formats, because
       some modules working correctly with GRASS native data,  can  produce  wrong  results  with
       input layers created by v.external.

       See  v.db.connect  for  an  example  of  maintaining  attributes  in external DBMS in also
       writable mode.

REFERENCES

       OGR vector library
       OGR vector library C API documentation

SEE ALSO

       v.clean, v.db.connect, v.in.db, v.in.ogr, v.out.ogr

AUTHOR

       Radim Blazek, ITC-Irst, Trento, Italy

       Last changed: $Date: 2012-02-25 05:38:11 -0800 (Sat, 25 Feb 2012) $

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       © 2003-2013 GRASS Development Team