Ubuntu Manpage: v.in.ogr - Imports vector data into a GRASS vector map using OGR library.

Provided by: grass-doc_7.8.2-1build3_all

NAME

       v.in.ogr  - Imports vector data into a GRASS vector map using OGR library.

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]     [spatial=xmin,ymin,xmax,ymax[,xmin,ymin,xmax,ymax,...]]
       [where=sql_query]     [min_area=float]     [type=string[,string,...]]     [snap=float]    [location=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 location

       -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 supported by the OGR library) into the
current location and mapset.

If the layer parameter is not given, all available OGR layers are imported 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 parameter 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 region 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 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 -f prints a
list of the vector formats supported by the system’s OGR (Simple Features Library). 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.

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-topological 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 original polygon. An original polygon will thus be converted to
multiple areas 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 report an error message
       ("Projection of dataset does not appear to match current location").

       If the user wishes to ignore the difference between the apparent coordinate 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 definition, it is possible to have
       v.in.ogr automatically create a new location 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 reprojects (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 PostgreSQL). The columns parameter is
used to define new column names during 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 column/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). Alternatively, 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. Note that recoding support is new for GDAL/OGR 1.9.0.

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 generated 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 attribute 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 areas.
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 ’avcimport’ (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 multilinestring(type = ’multilinestring’ or
type = ’route’).

• multipolygons: "relation" features that form a multipolygon (type = ’multipolygon’ or type =
’boundary’), and "way" features 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, ORACLE_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 geometry 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: "DefinicniBod", "OriginalniHranice" and
"GeneralizovanaHranice". By default v.in.ogr reads data from all three geometry columns. The user can
specify desired geometry column by geometry option, in this case the module will read geometry only from
the specified geometry column. In the example 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 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.

REFERENCES

           •   OGR vector library

           •   OGR vector library C API documentation

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)

       Main index | Vector index | Topics index | Keywords index | Graphical index | Full index

       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual