Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

I have QGIS with proj 4.8.0 installed. I'd like to add Winkel Tripel projection which seems to be defined as

+proj=wintri

But that definition string does not work. Is this a bug in my proj version, or what's the correct definition string?

share|improve this question
1  
Works for me: echo "34 -34" | proj "+proj=wintri" –  Paul Ramsey Nov 22 '12 at 4:17
1  
Yes, that echos something. But if I define a custom CRS with this string, nothing gets reprojected in QGIS. Guess I'd need some more parameters? –  underdark Nov 22 '12 at 6:42
4  
@Paul Ramsey: It seems that even though the Winkel Tripel projection is defined in the proj library and can be called from the command line, it can't be used as a custom CRS in QGIS because there's no inverse transformation in the proj library (see lists.maptools.org/pipermail/proj/2012-May/006302.html). And it seems that the inverse transformation isn't trivial (and will always be an approximation...). –  Jake Nov 23 '12 at 16:17
3  
I think you should write that into an answer, as it is... the answer. The command-line tools also refuse to do an inverse projection. –  Paul Ramsey Nov 23 '12 at 17:39
1  
As the collegues mentiond above, if you have also with proj +proj=aitoff have the same problems, it is a matter of missing inverse projection see: (+proj=aitoff; Rel. 4.7.1, 23 September 2009 <invproj>: inverse projection not available) and ( invproj +proj=wintri; Rel. 4.7.1, 23 September 2009 <invproj>: inverse projection not available ). Strange but good to know –  huckfinn Feb 7 at 23:18

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.