[gdal-dev] gdaladdo problems with compression

[Stefan Ziegler]

Thanks Even.

I was afraid that there will be no compression applied at all but this
behaviour is fine.

The geotiff where I add the overviews is the result of a gdalwarp process
(tiled, deflate, preditor=2). When I gdal_translate this geotiff with the
very same compression parameters I gain approx. 10 percent space. Sounds
this comprehensible? (I'm pretty sure there was once some discussion on the
mailing list but couldn't find anything).

regards
Stefan

On Mon, Sep 14, 2015 at 11:56 AM, Even Rouault <even.rouault at spatialys.com>
wrote:

> Le lundi 14 septembre 2015 11:46:45, Stefan Ziegler a écrit :
> > Hi
> >
> > we are facing problems with the compression of the overviews we are
> adding
> > with gdaladdo. The filesize does not differ whether we are using
> > compression parameters or not. The filesize of the input raster is
> approx.
> > 100 mb. The following both commands resulting in an identical filesize of
> > approx. 140mb.
> >
> > gdaladdo -r average  591252_12_5cm.tif 2 4 8 16 32
> >
> > gdaladdo -r average --config COMPRESS_OVERVIEW JPEG --config
> > PHOTOMETRIC_OVERVIEW YCBCR --config INTERLEAVE_OVERVIEW PIXEL
> > 591252_12_5cm.tif 2 4 8 16 32
>
> Stefan,
>
> The config options are only used for external overviews (-ro flag). For
> internal
> overviews, the same compression scheme as the full resolution image is
> used.
> In theory they could also use a different compression scheme, but this
> isn't
> currently implemented.
>
> Even
>
> >
> > The input raster is tiled and compressed with deflate (and predictor=2)
> >
> > I would expect that the latter one would be smaller. Did we misunderstand
> > something? Or do we use the parameters the wrong way?
> >
> > GDAL 1.11.2 and dev.
> >
> > regards
> > Stefan
>
> --
> Spatialys - Geospatial professional services
> http://www.spatialys.com
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20150914/77c3aea1/attachment.html>