Hi, I've been trying to create a lossless JPEG2000 image from a signed 16-bit DEM (stored in a TIFF file), but have had no success so far with JP2KAK. My DEM has large NoData regions (value is DTED NoData : -32767) I tried different GDAL versions (1.7 1.8), and different versions of KAKADU (6.3, 6.2) I'm using gdal_translate -of JP2KAK -co QUALITY=100 <input.tif> <output.tif> The image is created with no errors, but shows strong artefacts around Nodata parts, while the large NoData areas are transformed to random 16bit garbage. It's not a solution to use lossy conversion, because NoData values would be lost. However, using kakadu tools there is no problem : Creversible is used instead of QUALITY=100 kdu_compress.exe -i <source>.tif -o <target>.jp2 Clayers=12 Creversible=yes So I guess the problem comes from GDAL JP2KAK driver. A quick look at the code gave me no clue. I also checked if it was coming from the signed type (Int16), but that problem also occurs with unsigned 16-bit data (same data with a +32768 offset to have positive values) thanks in advance for any hint, best regards, Frederic Claudel
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