[gdal-dev] ecw speckling in no-data area

[Frank Warmerdam]

Ray D. Joslyn wrote:
> Is there any way to remove the speckling in ecw files in no-data areas 
> and re-output to ecw?  There doesn’t seem to be a compression scheme for 
> ecw that doesn’t produce these artifacts.  I have tried the nearblack 
> utility, but it doesn’t seem to be able to create or re-write to an ecw 
> file.

Ray,

To the best of my knowledge ecw compression is lossy, and not suitable to
exactly represent nodata areas with a specific value.  If you want to recover
nodata areas you need to use nearblack, writing to a new uncompressed (or at
least lossly compressed) output file in a format other than mrsid, or ecw.

Best regards,
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