EnglishFrenchSpanish

OnWorks favicon

v.externalgrass - Online in the Cloud

Run v.externalgrass in OnWorks free hosting provider over Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator

This is the command v.externalgrass that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator

PROGRAM:

NAME


v.external - Creates a new pseudo-vector map as a link to an OGR-supported layer or a
PostGIS feature table.

KEYWORDS


vector, import, external, OGR, PostGIS

SYNOPSIS


v.external
v.external --help
v.external [-fltb] input=string layer=name [output=name] [--overwrite] [--help]
[--verbose] [--quiet] [--ui]

Flags:
-f
List supported formats and exit

-l
List available layers in data source and exit

-t
List available layers including feature type in data source and exit
Format: layer name,type,projection check,geometry

-b
Do not build topology

--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 input OGR or PostGIS data source
Examples:
ESRI Shapefile: directory containing a shapefile
MapInfo File: directory containing a mapinfo file
PostGIS database: connection string, eg. ’PG:dbname=db user=grass’

layer=name [required]
Name of OGR layer or PostGIS feature table to be linked
Examples:
ESRI Shapefile: shapefile name
MapInfo File: mapinfo file name
PostGIS database: table name

output=name
Name for output GRASS vector map (default: input layer)

DESCRIPTION


v.external creates new vector map as a link to external OGR layer or PostGIS feature
table. OGR (Simple Features Library) is part of the GDAL library, so you need to install
GDAL to use v.external for external OGR layers. Note that a PostGIS feature table can be
linked also using built-in GRASS-PostGIS data driver (requires GRASS to be built with
PostgreSQL support).

Supported OGR vector formats
To list supported OGR formats, type
v.external -f
For details see OGR web site.

EXAMPLES


ESRI Shapefile
Assuming that ’test_shape.shp’ is located in directory ’/home/user/shape_data’.
v.external input=/home/user/shape_data layer=test_shape output=grass_map

MapInfo files
v.external input=./ layer=mapinfo_test output=grass_map

SDTS files
Note: you have to select the CATD file
v.external input=CITXCATD.DDF output=cities

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

PostGIS layers
PostGIS links are by default created by built-in PostGIS support, ie. using GRASS-PostGIS
data driver. If the environment variable GRASS_VECTOR_OGR exists, or GRASS is compiled
without PostgreSQL support then GRASS will use OGR-PostgreSQL driver for creating a link.
v.external input="PG:host=localhost user=postgres dbname=postgis" layer=polymap

NOTES


The simple feature data model used by OGR (or PostGIS) 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 two
formats, because some modules working correctly with GRASS native data, can produce wrong
results with input vector maps 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 C API documentation

Use v.externalgrass online using onworks.net services


Free Servers & Workstations

Download Windows & Linux apps

  • 1
    SuiteCRM
    SuiteCRM
    SuiteCRM is the award-winning Customer
    Relationship Management (CRM)
    application brought to you by authors
    and maintainers, SalesAgility. It is the
    world�s mos...
    Download SuiteCRM
  • 2
    Poweradmin
    Poweradmin
    Poweradmin is a web-based DNS
    administration tool for PowerDNS server.
    The interface has full support for most
    of the features of PowerDNS. It has full
    support...
    Download Poweradmin
  • 3
    Gin Web Framework
    Gin Web Framework
    Gin is an incredibly fast web framework
    written in Golang that can perform up to
    40 times faster, thanks to its
    martini-like API and custom version of
    httprout...
    Download Gin Web Framework
  • 4
    CEREUS LINUX
    CEREUS LINUX
    CEREUS LINUX basado en MX LINUX con
    varios entornos de escritorios. This is
    an application that can also be fetched
    from
    https://sourceforge.net/projects/cereu...
    Download CEREUS LINUX
  • 5
    Task Coach
    Task Coach
    Task Coach - Your friendly task
    manager. Task Coach is a free open
    source todo manager. It grew out of
    frustration about other programs not
    handling composite ...
    Download Task Coach
  • 6
    HyperSQL Database Engine (HSQLDB)
    HyperSQL Database Engine (HSQLDB)
    HSQLDB is a relational database engine
    written in Java, with a JDBC driver,
    conforming to ANSI SQL:2016. A small,
    fast, multithreaded engine and server
    with mem...
    Download HyperSQL Database Engine (HSQLDB)
  • More »

Linux commands

Ad