v.external(1)

1v.external(1)                 Grass User's Manual                v.external(1)
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NAME

6       v.external   -  Create  a  new vector as a read-only link to OGR layer.
7       Available      drivers:      ESRI       Shapefile,MapInfo       File,UK
8       .NTF,SDTS,TIGER,S57,VRT,AVCBin,REC,Mem‐
9       ory,CSV,GML,KML,SQLite,DODS,ODBC,PGeo,OGDI,PostgreSQL,MySQL,GRASS
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KEYWORDS

12       vector
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SYNOPSIS

15       v.external
16       v.external help
17       v.external dsn=string  [output=name]   [layer=string]   [--overwrite]
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19   Flags:
20       --overwrite
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22   Parameters:
23       dsn=string
24           OGR datasource name. Examples:
25                     ESRI    Shapefile:    directory     containing     shape‐
26           files        MapInfo File: directory containing mapinfo files
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28       output=name
29           Output vector, if not given, available layers are printed only
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31       layer=string
32           OGR  layer  name.  If not given, available layers are printed only.
33           Examples:
34                     ESRI  Shapefile:  shapefile  name          MapInfo  File:
35           mapinfo file name
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DESCRIPTION

38       v.external  creates  new  vector  as a link to external OGR layer (read
39       only).  OGR (Simple Features Library) is part of the GDAL  library,  so
40       you need to install GDAL to use v.external and external OGR layers.
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42   Supported OGR Vector Formats
43       ESRI Shapefile
44       Mapinfo File
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46       Further available drivers such as UK .NTF, SDTS, TIGER, IHO S-57 (ENC),
47       DGN, GML, AVCBin, REC, Memory, OGDI, and PostgreSQL depend on the local
48       installation (OGR library), for details see OGR web site.
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EXAMPLES

51       SHAPE files
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53       v.external dsn=/home/user/shape_data layer=test_shape output=grass_map
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56       MapInfo files
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58       v.external dsn=./ layer=mapinfo_test output=grass_map
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61       SDTS files (you have to select the CATD file)
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63       v.external dsn=CITXCATD.DDF output=cities
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66       TIGER files
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68       v.external     dsn=input/2000/56015/    layer=CompleteChain,PIP    out‐
69       put=t56015_all
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72       PostGIS maps (area example)
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74       v.external   dsn="PG:host=localhost    user=postgres    dbname=postgis"
75       layer=polymap \
76       output=polygons
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NOTES

80       The  simple  feature  data model used by OGR is very different from the
81       topological format used by GRASS. Instead of true topology,  so  called
82       'pseudo  topology'  is  created  for  data  linked by v.external.  User
83       should learn the difference between those to formats, because some mod‐
84       ules  working  correctly  with  GRASS  native  data,  can produce wrong
85       results with input layers created by v.external.
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87       See v.db.connect for an example of maintaining attributes  in  external
88       DBMS in also writeable mode.
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REFERENCES

91       OGR vector library
92       OGR vector library C API documentation
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AUTHOR

98       Radim Blazek, ITC-Irst, Trento, Italy
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100       Last changed: $Date: 2006/03/21 18:22:37 $
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102       Full index
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106GRASS 6.2.2                                                      v.external(1)