[gdal-dev] Nodata values in RGB orthoimages (GeoTiff)

[Neumann, Andreas]

Hi, 

Is there a way to store nodata values in GeoTiffs that don't match an
RGB value? I used either white or black as nodata values, but in some
rare cases these black or white pixel values do appear as valid data in
the image. 

How can I properly store nodata values in RGB Orthoimages in GeoTiffs
where the borders aren't purely rectangular? 

Would I have to use a hard mask for regions where there is no data, or
is there a trick with an alpha band? 

Thank you for any hints and greetings, 

Andreas 

  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20161122/e5b81e83/attachment.html>