1v.import(1) Grass User's Manual v.import(1)
2
6 v.import - Imports vector data into a GRASS vector map using OGR
7 library and reprojects on the fly.
8
10 vector, import, projection
11
13 v.import
14 v.import --help
15 v.import [-flo] input=string [layer=string[,string,...]] [out‐
16 put=name] [extent=string] [encoding=string] [snap=float]
17 [epsg=integer] [datum_trans=integer] [--overwrite] [--help]
18 [--verbose] [--quiet] [--ui]
19 Flags:
21 -f
22 List supported OGR formats and exit
23 -l
25 List available OGR layers in data source and exit
26 -o
28 Override projection check (use current location’s projection)
29 Assume that the dataset has the same projection as the current
30 location
31 --overwrite
33 Allow output files to overwrite existing files
34 --help
36 Print usage summary
37 --verbose
39 Verbose module output
40 --quiet
42 Quiet module output
43 --ui
45 Force launching GUI dialog
46 Parameters:
48 input=string [required]
49 Name of OGR datasource to be imported
50 layer=string[,string,...]
52 OGR layer name. If not given, all available layers are imported
53 output=name
55 Name for output vector map (default: input)
56 extent=string
58 Output vector map extent
59 Options: input, region
60 Default: input
61 input: extent of input map
62 region: extent of current region
63 encoding=string
65 Encoding value for attribute data
66 snap=float
68 Snapping threshold for boundaries (map units)
69 A suitable threshold is estimated during import
70 Default: -1
71 epsg=integer
73 EPSG projection code
74 Options: 1-1000000
75 datum_trans=integer
77 Index number of datum transform parameters
78 -1 to list available datum transform parameters
79 Options: -1-100
80
82 v.import imports vector data from files and database connections sup‐
83 ported by the OGR library) into the current location and mapset. If the
84 projection of the input does not match the projection of the location,
85 the input is reprojected into the current location. In case that the
86 projection of the input map does match the projection of the location,
87 the input is imported directly.
88 Supported Vector Formats
90 v.import uses the OGR library which supports various vector data for‐
91 mats including ESRI Shapefile, Mapinfo File, UK .NTF, SDTS, TIGER, IHO
92 S-57 (ENC), DGN, GML, GPX, AVCBin, REC, Memory, OGDI, and PostgreSQL,
93 depending on the local OGR installation. For details see the OGR web
94 site. The OGR (Simple Features Library) is part of the GDAL library,
95 hence GDAL needs to be installed to use v.in.ogr.
96 The list of actually supported formats can be printed by -f flag.
98
100 v.import checks the projection metadata of the dataset to be imported
101 against the current location’s projection. If not identical a related
102 error message is shown.
103 To override this projection check (i.e. to use current location’s pro‐
104 jection) by assuming that the dataset has the same projection as the
105 current location the -o flag can be used. This is also useful when geo‐
106 data to be imported do not contain any projection metadata at all. The
107 user must be sure that the projection is identical in order to avoid to
108 introduce data errors.
109 Topology cleaning
111 When importing polygons, non-topological polygons are converted to
112 topological areas. If the input polygons contain errors (unexpected
113 overlapping areas, small gaps between polygons, or warnings about being
114 unable to calculate centroids), the import might need to be repeated
115 using a snap value as suggested in the output messages.
116 The snap threshold defines the maximal distance from one to another
118 vertex in map units (for latitude-longitude locations in degrees). If
119 there is no other vertex within snap distance, no snapping will be
120 done. Note that a too large value can severely damage area topology,
121 beyond repair.
122 Post-processing: Snapped boundaries may need to be cleaned with
124 v.clean, using its tools break,rmdupl,rmsa. For details, refer to the
125 v.clean manual page.
126
128 # import SHAPE file at full extent and reproject to current location projection
129 v.import input=research_area.shp output=research_area extent=input
130
132 SQL syntax errors
133 Depending on the currently selected SQL driver, error messages such as
134 follows may arise:
135 DBMI-SQLite driver error:
136 Error in sqlite3_prepare():
137 near "ORDER": syntax error
138 Or:
139 DBMI-DBF driver error:
140 SQL parser error:
141 syntax error, unexpected DESC, expecting NAME processing ’DESC
142 This indicates that a column name in the input dataset corresponds to a
143 reserved SQL word (here: ’ORDER’ and ’DESC’ respectively). A different
144 column name has to be used in this case. The columns parameter can be
145 used to assign different column names on the fly in order to avoid
146 using reserved SQL words. For a list of SQL reserved words for SQLite
147 (the default driver), see here.
148 Projection errors
150 Projection of dataset does not appear to match the current location.
151 Here you need to create or use a location whose projection matches that
152 of the vector data you wish to import. Try using location parameter to
153 create a new location based upon the projection information in the
154 file. If desired, you can then re-project it to another location with
155 v.proj.
156
158 v.clean, v.in.lines, v.in.ogr, v.proj
159
161 Markus Metz
162 Improvements: Martin Landa, Anna Petrasova
163
165 Available at: v.import source code (history)
166 Main index | Vector index | Topics index | Keywords index | Graphical
168 index | Full index
169 © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual
171GRASS 7.8.2 v.import(1)