[gdal-dev] Why COG does not support predictor=3?

Even Rouault even.rouault at spatialys.com
Fri Jan 10 05:45:53 PST 2020


Jukka,

> The cloud optimized GeoTIFF generator has a creation option PREDICTOR=YES
> that is Boolean. Tiffinfo reveals that it means that predictor=2 is used
> "Predictor: horizontal differencing 2 (0x2)". However, for floating point
> images predictor=3 could give much better compression. In a quick test with
> regular GeoTIFFs the difference between predictor=2 and predictor=3 was 218
> kB vs. 148 kB. The difference when using no predictor at all vs.
> predictor=2 was much less, only 227 kB vs. 218 kB.  Is there some special
> reason for dropping the predictor=3 support from COG?

Adressed by
https://github.com/OSGeo/gdal/commit/0c520d04d17669499cbbfc3c2d87258144263947

Even

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