[gdal-dev] ReprojectImage and nodata

[Even Rouault]

Le mercredi 23 octobre 2013 19:05:18, Ochs, Elke ERDC-RDE-CRREL-NH a écrit :
> ReprojectImage does not maintain areas of nodata as I would expect it
> should.  Small areas of nodata are getting erased and larger areas are
> reduced in size.  I'm reprojecting from geographic to Albers, using
> approximately the same  cell size (converted from dd to meters).  I'm
> using GDAL 1.9.2 in Python.
> 
> Gdalwarp does a better job of maintaining nodata cells.  Is there a way to
> get ReprojectImage to handle nodata in a similar way?  

Elke,

Always difficult to diagnose those problems as there are a few variables to 
consider.
Looking at the code of GDALReprojectImage(), I see it should take into account 
the source nodata value, but it will ignore the nodata value that you may have 
set on the target dataset, contrary to gdalwarp. That might be your issue. 
Your source nodata values are likely to become 0 in the target datasource.

Even

-- 
Geospatial professional services
http://even.rouault.free.fr/services.html