[gdal-dev] Potential issue with gdaladdo overviews setting alpha channel to nodata value instead of zero

[Even Rouault]

On vendredi 6 octobre 2017 13:01:29 CEST Tim Waters wrote:
> Even,
> 
> Many thanks! This did fix the issue.
> Agreed, having both nodata and transparency would confuse things, and I see
> that this way also ensures that it works well with cropped maps with pure
> black pixels.

I've changed in trunk the behaviour of gdalwarp as I suggested:
https://trac.osgeo.org/gdal/ticket/7075

The current behaviour is very likely a unintended side-effect of a GDAL 1.11.0 change: 
* gdalwarp: copy nodata values from source to dest if -dstnodata is not given ; add option 
to not set dest nodata with -dstnodata None (#5087)

Even

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