[gdal-dev] gdaladdo, overviews and NODATA

[Frank Warmerdam]

On Tue, Feb 21, 2012 at 1:17 PM, Armin Burger <armin.burger at gmx.net> wrote:
> Then I tried to set the NODATA value to 0 using Gdal-Python, and afterwards
> they had
>
> Band 1 Block=3000x1 Type=Byte, ColorInterp=Red
>  NoData Value=0
> Band 2 Block=3000x1 Type=Byte, ColorInterp=Green
>  NoData Value=0
> Band 3 Block=3000x1 Type=Byte, ColorInterp=Blue
>  NoData Value=0
>
> But the result was the same, when using "-r average" a 1-2 pixel area of the
> original NODATA values along the border to the DATA areas seem to have got
> pixels with higher values than 0 (at least in Mapserver they cannot any more
> be "hidden" with OFFSITE). Is there a simple way to write out the overviews
> to separate Tiff files so that I can check them directly?

Armin,

You can use the gdal/apps/dumpoverviews app to write out overviews.  It may
not be built and installed by default.   If you confirm the overviews are built
wrong then please file a ticket, and provide with it a small sample file with
which you encounter the problem.

Best regards,
-- 
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