[Gdal-dev] Creating compressed overviews

[Frank Warmerdam]

Daniel Bäck wrote:
> Hi!
> 
> Is it possible to generate compressed overviews for tiff files? I tried to generate overviews for with gdaladdo but the overviews aren't compressed. I tried to change the compress param in the call to TIFF_WriteOverview in GTIFFBuildOverviews from COMPRESSION_NONE to COMPRESSION_PACKBITS but then i get an error stating that inplace updates of compressed tiff isn't supported. Is there any way around this or did i make anything wrong?

Daniel,

Yikes!  This is a flaw in the code.  Would you mind filing a bug about it
in Bugzilla?

Ideally overviews within a TIFF file should be generated with the same
compression type as the base image.  It isn't clear how overview compression
should be handled when it is an external .ovr file though.  I neglected to
leave any way of passing extra options into the overview building method.

Best regards,

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