Dear Even, thanks for your response, finally I got it working. The main issue was that the global dataset had an extent e.g. on the most western border of -180.0044643 which caused the error (although strangely not always, because I tried the same command with the same dataset and sometime it worked...)
Anyhow, clipping the data before and then specifying as you suggested the target extent (-te) works now. Cheers, Michael 2012/8/1 Even Rouault <[email protected]> > Le mardi 31 juillet 2012 11:32:35, Michael Schulz a écrit : > > Dear GDAL'ers, > > > > I have currently some issues with reprojecting global datasets in > > geographic coordinates to the Mollweide projection (GDAL 1.8.0). When > using > > gdalwarp like: > > > > gdalwarp -s_srs 'EPSG:4326' -t_srs '+proj=moll +lon_0=0 +x_0=0 +y_0=0 > > +ellps=WGS84 +datum=WGS84 +units=m +no_defs' LatLon.2001.tree.nd.tif > > Mollweide.2001.tree.nd.tif > > > > unpredictably, it sometimes works but other times I get the "Too many > > points (441 out of 441) failed to transform" error. I was wondering > whether > > this could be a memory size issues (although the machine I'm working has > > 24GB RAM). > > No, memory isn't the reason. The reason is that the algorithm used by > gdalwarp > doesn't manage to guess the extent of the raster once reprojected. It may > or > may not succeed depending on the extent of the source image and the > reprojection involved. If you know the extent in the target coordinate > system, > specifying it with -te will solve that issue. > > > > > > To overcome this adding the config option CHECK_WITH_INVERT_PROJ FALSE > > works, but now the projected raster shows wrapped values outside the > actual > > valid coordinate range for Mollweide, e.g. the Aleutian Islands appear > > twice (once inside the outer ellipse. Is this due to > > the CHECK_WITH_INVERT_PROJ ? > > The default value of CHECK_WITH_INVERT_PROJ (YES) checks that when a > reprojection of a coordinate is done, the invert reprojection gives a > result > close to the original coordinate, which validates the fact that we are in > the > validity area of the reprojection. If you override with > CHECK_WITH_INVERT_PROJ=FALSE, you can have indeed strange artifacts due to > non > invertible transformations. > > > I haven't worked with the cutline option > > before, but should/could this be used here to solve this? > > I don't think this will help. > > > > > Happy about any feedback on this issue. Thanks, Michael > -- ----------------------------------------------------------- Michael Schulz Via Cime Bianche 10 IT-21023 Besozzo (VA)
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