Licensing options for this format begin with FME Professional Edition.
The VRT Raster reader allows FME to read data from VRT raster datasets.
Overview
VRT Raster is an XML format that maps its attributes and geometries to that of an underlying data source of any GDAL-supported raster format. In this way, the GDAL VRT Raster reader allows FME to read data from any GDAL format supported by FME.
Note that there is also a separate and comparable VRT format OGR Virtual Format for reading vector data through VRT files. These formats are not compatible.
VRT Raster is a gateway format that overlays other GDAL formats and the capabilities outlined in this document are a superset and are subject to some restrictions imposed by the underlying data format.
Reader Overview
The VRT reader outputs one or more raster feature for each input VRT file. Each VRT raster band is made of specified bands from specified raster source files. The reader considers a single .vrt file to be a VRT raster dataset.
VRT Features
Any band from any raster file supported by GDAL can be added to any VRT band allowing interesting composition of raster bands from different sources.
VRT Raster also allows for warping and pansharpening of underlying raster files. Metadata tags allow for adding metadata both to the overarching dataset, as well as specific VRT bands.
For more information on the specification of the GDAL VRT format, please see http://www.gdal.org/gdal_vrttut.html.
Coordinate Systems
The VRT Raster format supports all spatial reference systems recognized by the GDAL library. Specifying a spatial reference system in a VRT Raster dataset will override that of the underlying dataset (but will not reproject the underlying dataset).
FME Raster Features
FME raster features represent raster data and use several concepts that are unlike those used in the handling of vector data. The topics below describe how FME processes raster data.