Licensing options for this format begin with FME Professional Edition.
The OGR Virtual Dataset reader allows FME to read data from OGR VRT datasets.
Overview
OGR VRT is an XML format which maps its attributes and geometries to that of an underlying datasource of any OGR-supported format. In this way, the VRT reader allows FME to read data from any OGR format whose driver is provided with FME.
The VRT format is able to map its geometry to an encoded representation of the geometry. This allows VRT to overlay a non-spatial format (for example, CSV) that contains geometric data, and allow it to be treated as a spatial dataset with simple geometry types and a spatial reference system.
Because VRT is a gateway format that overlays other OGR formats, the capabilities outlined in this document are a superset and are subject to some restrictions imposed by the underlying data format. Some capabilities (for example, spatial reference systems) overlay and enhance the capabilities of the underlying data; however, other capabilities (for example, geometry types) will be reliant on the underlying data format.
The following OGR drivers are provided with FME:
- CSV
- Esri Shapefile
- Google Fusion Tables
- DGN
- EPI Info REC
- NTF
- TIGER
- ArcInfo Binary
- ArcInfo E00
- CouchDB
- GeoJSON
For more information on the specification of the VRT format, please see http://www.gdal.org/drv_vrt.html.
Reader Overview
The OGR VRT reader considers a single .vrt file to be a VRT dataset.
Coordinate Systems
The OGR VRT format supports all spatial reference systems recognized by the OGR library. Specifying a spatial reference system in a VRT dataset will override that of the underlying dataset. Spatial reference systems may be specified as follows:
- OGC Well Known Text definition
- EPSG:n - where n is a recognized ESPG code
- EPSGA:n - where n is a recognized ESPGA code
- AUTO:proj_id,unit_id,lon0,lat0 – WMS auto projections
- urn:ogc:crs:EPSG:n – OGC URNs
- PROJ.4 defintion
- Filename – file contents will be read as WKT, XML, or PROJ.4
- OGR well-known names (for example, NAD27, WGS84)
- ESRI WKT when prefixed with ESRI::