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I have a global elevation raster in latitude and longitude. I want to use it as the basemap in a world projection system (e.g., Mollweide, Robinson).

When I set the coordinate system to Mollweide (or Robinson) and enable on-the-fly projection, the global topography raster map disappears until I zoom in far enough that there is no "no data" area left in the display. In other words, I need to make sure that the display doesn't include any of the curved map projection edges.

I have tried using gdalwarp outside of QGIS as well, and then importing the already-projected raster, using gdalwarp:

gdalwarp -s_SRS 'EPSG:4326' -t_srs '+proj=moll +lon_0=0 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs' coarse_6am_topo_021000.tif out.tif

However, this projected map cuts off the north polar region (not sure why this is happening either), so I am not sure what to do -- it would be nice if the on-the-fly reprojection worked!

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According to https://lists.osgeo.org/pipermail/gdal-dev/2012-August/033674.html, gdalwarp (and OTF as well) fails on your use case.

The best workaround is to clip the raster to the real world, as described in Valid values of mollweide projection in QGis

  • Thank you for the help! To clarify for others wondering: the first link answers the GDAL question, while the second seems to be to help with the on-the-fly reprojection. – Andy Wickert Oct 9 '16 at 17:27
  • Unfortunately, clipping the raster as suggested here has not worked for me. I have also simply reduced the bounds of the raster, even in a quite extreme way (removing 10 degrees off each edge), with no success. – Andy Wickert Oct 10 '16 at 6:23
  • OTF does NOT work, you must reproject. Furthermore, try an ellipsoid instead of a sphere. – AndreJ Oct 10 '16 at 9:51

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