Hi Dane, On 05/25/2011 10:12 PM, Dane Springmeyer wrote: > re: contributing to the wiki - I would love help. I figured > adding/refactoring this page would be the place to start: > > http://trac.mapnik.org/wiki/Troubleshooting
Funny that you point me to that page, because the issue described on that page was another one I was running into (polygons across the dateline). But in my case I tried to use the +pm parameter of the PROJ.4 projection string to "rotate" the earth to a different center meridian on purpose. In this case neither clipping nor the +over parameter would help me, because with the first I would loose the geometry "coming out" on the other side, while with the second the whole projection would just be shifted and I would end up with a distorted projection that still has good ol' Greenwich at the center. I once wrote a simple map renderer in Java where I included a heuristic algorithm to split "wrapping" polygons in two on the fly while rendering -- detect the dateline crossover in the polygon's vertices, and in case it happens create a second polygon on the fly and assign subsequent vertices to it until it crosses back again. Would you be in favour of such a feature ever being introduced in Mapnik? I am not sure what the performance implications for the 99.9% of the cases that don't need that feature would be (I guess it should only be an optional rendering mode activated by a flag or something). If there are no fundamental objections against it, I could try to reproduce what I did in Java in the C++ code (given my coding skills are sufficient) Regarding the wiki, are you distinguishing between Mapnik and Mapnik2 (as there are maybe different solutions available, or even different problems), or is this just a temporary distinction? Best, Flo _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
