Le mercredi 23 octobre 2013 21:19:48, David Shean a écrit : > Even, > I encountered the issue you mention back in May: > > http://osgeo-org.1560.x6.nabble.com/gdal-dev-ReprojectImage-and-nodata-td50 > 57270.html > > The current ReprojectImage nodata handling is a bit confusing. Do you see > a relatively simple fix to mirror the behavior of gdalwarp?
Probably a matter of setting the padfDstNoData array to the target dataset nodata value, if that's the issue. There's also the INIT_DEST warping option that can play a role on this. > > Thanks. > -David > > On Oct 23, 2013, at 10:25 AM, Even Rouault <[email protected]> wrote: > > 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 _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
