Re: Fwd: GDAL COG+LERC compression
On 9/17/20 7:56 PM, Antonio Valentino wrote:
> today I tried to made some tests to generate Cloud Optimized Geotiff
> (COG) files with LERC compression.
>
> I realized that this is not possible in debian because, if I understand
> correctly, we build GDAL using system libtiff while the LERC compressor,
> according to [1], need the internal libtiff.
Yes, and that's somewhat broken by design.
libtiff should expose the features required by GDAL for this. IIRC GDAL
uses a private header currently.
We've had this discussion before, but I don't remember where, possibly
on #debian-gis.
As long as the internal copy of libtiff is required for this, we won't
be able to support it in Debian. Using the embedded copy of libtiff is
not an option, as it's too prone to security issues.
> Can you please confirm that my understanding is correct?
>
> The strange thing, to me, is that the same limitation also applies to
> the the ZSTD compressor [1], but in this case I'm perfectly able to
> generate COG files with ZSTD compression in debian.
>
> I gave a look to how we generate the package an haven't found no
> specific configuration/patch regarding this aspects, so I'm wondering if
> I'm missing something or if there is a small bug in the GDAL
> documentation of the COG driver [1].
>
> Do you have comments/hints?
>
> [1] https://gdal.org/drivers/raster/cog.html#raster-cog
Kind Regards,
Bas
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