JP2ECW -- ERMapper JPEG2000 (.jp2)

GDAL supports reading and writing JPEG2000 files using the ECW SDK from ERMapper.

Coordinate system and georeferencing transformations are read, and some degree of support is included for GeoJP2 (tm) (GeoTIFF-in-JPEG2000), ERMapper GML-in-JPEG2000, and the new GML-in-JPEG2000 specification developed at OGC.

Support for the JP2ECW driver in GDAL is optional, and requires linking in external ECW SDK libraries provided by ERMapper.

By default the ECW SDK will use up to one quarter of physical RAM for internal caching and work memory during decoding. This is normally fine, but the amount of memory to use can be adjusted by setting the GDAL_ECW_CACHE_MAXMEM configuration variable with an amount of memory in bytes. Config variables can be set in the environment or using the --config commandline switch.

Creation Issues

The free ECW compression kit only supports compression of images up to 500MB. To compress very large images it is necessary to license ECW technology from ERMapper. Creation of 8 bit, and 16bit signed or unsigned values is supported.

Creation Options:

JPEG2000 format does not support creation of overviews since the format is already considered to be optimized for "arbitrary overviews".

See Also: