v.in.ogr(1grass) GRASS GIS User's Manual v.in.ogr(1grass)
NAME
v.in.ogr - Imports vector data into a GRASS vector map using OGR li-
brary.
KEYWORDS
vector, import, OGR, topology, geometry, snapping, create location
SYNOPSIS
v.in.ogr
v.in.ogr --help
v.in.ogr [-flc2tojrewi] input=string [gdal_config=string]
[gdal_doo=string] [layer=string[,string,...]] [output=name] [spa-
tial=xmin,ymin,xmax,ymax[,xmin,ymin,xmax,ymax,...]] [where=sql_query]
[min_area=float] [type=string[,string,...]] [snap=float] [loca-
tion=name] [columns=name[,name,...]] [encoding=string]
[key=string] [geometry=name] [--overwrite] [--help] [--verbose]
[--quiet] [--ui]
Flags:
-f
List supported OGR formats and exit
-l
List available OGR layers in data source and exit
-c
Do not clean polygons (not recommended)
-2
Force 2D output even if input is 3D
Useful if input is 3D but all z coordinates are identical
-t
Do not create attribute table
-o
Override projection check (use current location’s projection)
Assume that the dataset has the same projection as the current lo-
cation
-j
Perform projection check only and exit
-r
Limit import to the current region
-e
Extend region extents based on new dataset
Also updates the default region if in the PERMANENT mapset
-w
Change column names to lowercase characters
-i
Create the location specified by the "location" parameter and exit.
Do not import the vector data.
--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
Examples:
ESRI Shapefile: directory containing shapefiles
MapInfo File: directory containing mapinfo files
gdal_config=string
GDAL configuration options
Comma-separated list of key=value pairs
gdal_doo=string
GDAL dataset open options
Comma-separated list of key=value pairs
layer=string[,string,...]
OGR layer name. If not given, all available layers are imported
Examples:
ESRI Shapefile: shapefile name
MapInfo File: mapinfo file name
output=name
Name for output vector map
spatial=xmin,ymin,xmax,ymax[,xmin,ymin,xmax,ymax,...]
Import subregion only
Format: xmin,ymin,xmax,ymax - usually W,S,E,N
where=sql_query
WHERE conditions of SQL statement without ’where’ keyword
Example: income < 1000 and population >= 10000
min_area=float
Minimum size of area to be imported (square meters)
Smaller areas and islands are ignored. Should be greater than
snap^2
Default: 0.0001
type=string[,string,...]
Optionally change default input type
Options: point, line, boundary, centroid
Default:
point: import area centroids as points
line: import area boundaries as lines
boundary: import lines as area boundaries
centroid: import points as centroids
snap=float
Snapping threshold for boundaries (map units)
’-1’ for no snap
Default: -1
location=name
Name for new location to create
columns=name[,name,...]
List of column names to be used instead of original names, first is
used for category column
encoding=string
Encoding value for attribute data
Overrides encoding interpretation, useful when importing ESRI
Shapefile
key=string
Name of column used for categories
If not given, categories are generated as unique values and stored
in ’cat’ column
geometry=name
Name of geometry column
If not given, all geometry columns from the input are used
DESCRIPTION
v.in.ogr imports vector data from files and database connections sup-
ported by the OGR library) into the current location and mapset.
If the layer parameter is not given, all available OGR layers are im-
ported as separate GRASS layers into one GRASS vector map. If several
OGR layer names are given, all these layers are imported as separate
GRASS layers into one GRASS vector map.
The optional spatial parameter defines spatial query extents. This pa-
rameter allows the user to restrict the region to a spatial subset
while importing the data. All vector features completely or partially
falling into this rectangle subregion are imported. The -r current re-
gion flag is identical, but uses the current region settings as the
spatial bounds (see g.region).
Supported Vector Formats
v.in.ogr uses the OGR library which supports various vector data for-
mats 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 format
overview. The -f prints a list of the vector formats supported by the
system’s OGR (Simple Features Library). The OGR (Simple Features Li-
brary) 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.
Topology cleaning
Topology cleaning on areas is automatically performed, but may fail in
special cases. In these cases, a snap threshold value is estimated from
the imported vector data and printed out at the end. The vector data
can then be imported again with the suggested snap threshold value
which is incremented by powers of 10 until either an estimated upper
limit for the threshold value is reached or the topology cleaning on
areas was successful. In some cases, manual cleaning might be required
or areas are truly overlapping, e.g. buffers created with non-topologi-
cal software.
The min_area threshold value is being specified as area size in map
units with the exception of latitude-longitude locations in which it is
being specified solely in square meters.
The snap threshold value is used to snap boundary vertices to each
other if the distance in map units between two vertices is not larger
than the threshold. Snapping is by default disabled with -1. See also
the v.clean manual.
Overlapping polygons
When importing overlapping polygons, the overlapping parts will become
new areas with multiple categories, one unique category for each origi-
nal polygon. An original polygon will thus be converted to multiple ar-
eas with the same shared category. These multiple areas will therefore
also link to the same entry in the attribute table. A single category
value may thus refer to multiple non-overlapping areas which together
represent the original polygon overlapping with another polygon. The
original polygon can be recovered by using v.extract with the desired
category value or where statement and the -d flag to dissolve common
boundaries.
Location Creation
v.in.ogr attempts to preserve projection information when importing
datasets if the source format includes projection information, and if
the OGR driver supports it. If the projection of the source dataset
does not match the projection of the current location v.in.ogr will re-
port an error message ("Projection of dataset does not appear to match
current location").
If the user wishes to ignore the difference between the apparent coor-
dinate system of the source data and the current location, they may
pass the -o flag to override the projection check.
If the user wishes to import the data with the full projection defini-
tion, it is possible to have v.in.ogr automatically create a new loca-
tion based on the projection and extents of the file being read. This
is accomplished by passing the name to be used for the new location via
the location parameter. Upon completion of the command, a new location
will have been created (with only a PERMANENT mapset), and the vector
map will have been imported with the indicated output name into the
PERMANENT mapset.
An interesting wrapper command around v.in.ogr is v.import which repro-
jects (if needed) the vector dataset during import to the projection of
the current location.
NOTES
Table column names: supported characters
The characters which are eligible for table column names are limited by
the SQL standard. Supported are:
[A-Za-z][A-Za-z0-9_]*
This means that SQL neither supports ’.’ (dots) nor ’-’ (minus) nor ’#’
in table column names. Also a table name must start with a character,
not a number.
v.in.ogr converts ’.’, ’-’ and ’#’ to ’_’ (underscore) during import.
The -w flag changes capital column names to lowercase characters as a
convenience for SQL usage (lowercase column names avoid the need to
quote them if the attribute table is stored in a SQL DBMS such as Post-
greSQL). The columns parameter is used to define new column names dur-
ing import.
The DBF database specification limits column names to 10 characters.
If the default DB is set to DBF and the input data contains longer col-
umn/field names, they will be truncated. If this results in multiple
columns with the same name then v.in.ogr will produce an error. In
this case you will either have to modify the input data or use
v.in.ogr’s columns parameter to rename columns to something unique.
(hint: copy and modify the list given with the error message). Alter-
natively, change the local DB with db.connect.
File encoding
When importing ESRI Shapefiles the OGR library tries to read the
LDID/codepage setting from the .dbf file and use it to translate string
fields to UTF-8. LDID "87 / 0x57" is treated as ISO8859_1 which may not
be appropriate for many languages. Unfortunately it is not clear what
other values may be appropriate (see example below). To change encoding
the user can set up SHAPE_ENCODING environmental variable or simply to
define encoding value using encoding parameter.
Value for encoding also affects text recoding when importing DXF files.
For other formats has encoding value no effect.
Defining the key column
Option key specifies the column name used for feature categories. This
column must be integer. If not specified, categories numbers are gener-
ated starting with 1 and stored in the column named "cat".
Supports of multiple geometry columns
Starting with GDAL 1.11 the library supports multiple geometry columns
in OGR. By default v.in.ogr reads all geometry columns from given
layer. The user can choose desired geometry column by geometry option,
see example below.
Latitude-longitude data: Vector postprocessing after import
For vector data like a grid, horizontal lines need to be broken at
their intersections with vertical lines (v.clean ... tool=break).
EXAMPLES
The command imports various vector formats:
SHAPE files
v.in.ogr input=/home/user/shape_data/test_shape.shp output=grass_map
Alternate method:
v.in.ogr input=/home/user/shape_data layer=test_shape output=grass_map
Define encoding value for attribute data (in this example we expect at-
tribute data in Windows-1250 encoding; ie. in Central/Eastern European
languages that use Latin script, Microsoft Windows encoding).
v.in.ogr input=/home/user/shape_data/test_shape.shp output=grass_map encoding=cp1250
MapInfo files
v.in.ogr input=./ layer=mapinfo_test output=grass_map
Arc Coverage
We import the Arcs and Label points, the module takes care to build ar-
eas.
v.in.ogr input=gemeinden layer=LAB,ARC type=centroid,boundary output=mymap
E00 file
See also v.in.e00.
First we have to convert the E00 file to an Arc Coverage with ’avcim-
port’ (AVCE00 tools, use e00conv first in case that avcimport fails):
avcimport e00file coverage
v.in.ogr input=coverage layer=LAB,ARC type=centroid,boundary output=mymap
SDTS files
You have to select the CATD file.
v.in.ogr input=CITXCATD.DDF output=cities
TIGER files
v.in.ogr input=input/2000/56015/ layer=CompleteChain,PIP output=t56015_all \
type=boundary,centroid snap=-1
PostGIS tables
Import polygons as areas:
v.in.ogr input="PG:host=localhost dbname=postgis user=postgres" layer=polymap \
output=polygons type=boundary,centroid
If the table containing the polygons are in a specific schema, you can
use:
v.in.ogr input="PG:host=localhost dbname=postgis user=postgres" \
layer=myschema.polymap \
output=polygons type=boundary,centroid
Generally, v.in.ogr just follows the format-specific syntax defined by
the OGR library.
OpenStreetMap (OSM)
OSM data are available in .osm (XML based) and .pbf (optimized binary)
formats. The .pbf format is recommended because file sizes are smaller.
The OSM driver will categorize features into 5 layers :
• points: "node" features that have significant tags attached.
• lines: "way" features that are recognized as non-area.
• multilinestrings: "relation" features that form a multi-
linestring(type = ’multilinestring’ or type = ’route’).
• multipolygons: "relation" features that form a multipolygon
(type = ’multipolygon’ or type = ’boundary’), and "way" fea-
tures that are recognized as area.
• other_relations: "relation" features that do not belong to any
of the above layers.
It is recommended to import one layer at a time, and to select features
with the where option, e.g. to import roads, use
v.in.ogr where="highway <> ’’"
i.e. the OSM tag highway must be set.
When importing administrative boundaries from OSM, it is important to
not only select administrative boundaries, but also the admin level to
be imported (valid range is 1 - 11), e.g. with
v.in.ogr where="boundary = ’administrative’ and admin_level = ’1’"
The OSM topological model differs from the GRASS topological model. OSM
topologically correct connections of lines can be on all vertices of a
line. During import, lines are automatically split at those vertices
where an OSM connection to another line exists.
Import of OSM data requires a configuration file, defined with the
OSM_CONFIG_FILE configuration option. In the data folder of the GDAL
distribution, you can find a osmconf.ini file that can be customized to
fit your needs. See OSM map features for keys and their values. You
should set "other_tags=no" to avoid problems with import or querying
the imported vector. Once a OSM_CONFIG_FILE has been created, OSM data
can be imported with e.g.
export OSM_CONFIG_FILE=/path/to/osmconf.ini
v.in.ogr input=name.pbf layer=lines output=osm_data
Oracle Spatial
Note that you have to set the environment-variables ORACLE_BASE, ORA-
CLE_SID, ORACLE_HOME and TNS_ADMIN accordingly.
v.in.ogr input=OCI:username/password@database_instance output=grasslayer layer=roads_oci
Multiple geometry columns
This example shows how to work with data which contain multiple geome-
try per feature. The number of geometry columns per feature can be
checked by v.external together with -t flag.
v.external -t input=20141130_ST_UKSH.xml.gz
...
Okresy,point,1,DefinicniBod
Okresy,multipolygon,1,OriginalniHranice
Okresy,multipolygon,1,GeneralizovaneHranice
...
In our example layer "Okresy" has three geometry columns: "Definicni-
Bod", "OriginalniHranice" and "GeneralizovanaHranice". By default
v.in.ogr reads data from all three geometry columns. The user can spec-
ify desired geometry column by geometry option, in this case the module
will read geometry only from the specified geometry column. In the ex-
ample below, the output vector map will contain only geometry saved in
"OriginalniHranice" geometry column.
v.in.ogr input=20141130_ST_UKSH.xml.gz layer=Okresy geometry=OriginalniHranice
WARNINGS
If a message like
WARNING: Area size 1.3e-06, area not imported
appears, the min_area may be adjusted to a smaller value so that all
areas are imported. Otherwise tiny areas are filtered out during import
(useful to polish digitization errors or non-topological data).
If a message like
Try to import again, snapping with at least 1e-008: ’snap=1e-008’
appears, then the map to be imported contains topological errors. The
message suggests a value for the snap parameter to be tried. For more
details, see above in Topology Cleaning.
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 us-
ing 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.
REFERENCES
• OGR vector library
• OGR vector library C API documentation
SEE ALSO
db.connect, v.clean, v.extract, v.build.polylines, v.edit, v.external,
v.import, v.in.db, v.in.e00, v.out.ogr
GRASS GIS Wiki page: Import of Global datasets
AUTHORS
Original author: Radim Blazek, ITC-irst, Trento, Italy
Location and spatial extent support by Markus Neteler and Paul Kelly
Various improvements by Markus Metz
Multiple geometry columns support by Martin Landa, OSGeoREL, Czech
Technical University in Prague, Czech Republic
SOURCE CODE
Available at: v.in.ogr source code (history)
Accessed: unknown
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