I have a shapefile in Wagner VII projection (well, the proj4 string really only is: "+proj=wag7 +datum=WGS84 +units=m"). I'd like to reproject it to WGS84 (EPSG:4326) using QGIS 2.6. However, when I try to do so, the program outputs an error message, telling me that the forward projection was not successful, with the following error: "non-convergent inverse meridional dist". What am I doing wrong?
It seems that the proj.4 implementation of Wagner VII does not have a definition for the inverse projection:
proj -I +proj=wag7 Rel. 4.8.0, 6 March 2012 <proj>: inverse projection not available program abnormally terminated
In this case, no reprojection is possible.
See also this ticket on similar problems: http://trac.osgeo.org/proj/ticket/234