[gdal-dev] gdalwarp and Molleweide projections

[Matthew Vavrek]

I have just started trying to use gdalwarp and gdal_translate to 
reproject some world maps. I have managed to achieve some limited 
success with some projections, but I seem to get strange results with my 
images, especially with Mollweide. The Molleweide gives a horizontally 
flipped image, sometimes with an unreversed strip in the middle, and the 
top and bottom of the image seem stretched rather than compressed as I 
would expect. The code I used to translate is:

gdalwarp -of GTiff -s_srs EPSG:4326 -t_srs EPSG:54009 input.tif 
moll-output.tif

I also tried with -t_srs '+proj=moll +lon_0=0'.
My initial image was a plain jpg, and I have tried creating a world file 
and using gdal_translate to georeference the image. I also tried using:

gdalwarp s_srs EPSG:4326 t_srs EPSG:4326 input.tif output.tif

to see if that would help, which it oddly did for some of the other 
projections I was trying (like polyconic). I have even tried different 
world map images, yet still get these strange results. I can't figure 
out what I'm doing wrong to get these totally bizarre images, so any 
help would be appreciated.

Thanks
Matthew