Hi, Nodata values with lossy compression like JPEG, ECW, or JPEG2000 do not really work. I noticed that newest ECW SDK versions (>= 4) have support for using a transparency mask:
http://blog.hexagongeospatial.com/help-ecw-speckled-edges/ "Using the ECWJP2 SDK terminology, a transparency mask is implemented as an opacity band called AllOpacity." GDAL ECW driver does not have support for this. I wonder if it could be doable and if I should make a feature request. I also wonder if GDAL can decode ECW files which have transparency mask correctly. -Jukka Rahkonen- _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
