Martin Desruisseaux ha scritto: > Sometime it is good to forget a little bit about a problem, have a good night > and think again about it the day after. I believe that we can handle this > issue > in a finer way than brute force. > > There is my assumption, please correct me if I'm wrong: > > The problem arise because the Envelope to be projected contains a singularity > point in the target CRS (namely the South pole). If the South Pole was not > inside the Envelope to be projected (even if it is very close), the problem > would not arise. > > The South Pole is a singularity point in GeographicCRS because we reach the > maximal value allowed on one particular geographic axis, namely latitude. This > point is not a singularity in the stereographic projection, where axis extends > toward infinity in all directions (mathematically). I means, on a pure > mathematic point of view the South pole has nothing special in Stereographic > projection, apart being the origin (0,0). > > So what we may want to do is: check if an envelope in *source* CRS contains > any > of the singularity point that may exists in the *target* CRS. If such point > are > found, add them to the transformed envelope.
Hum, thinking about it, the issue not only adding the singularity point, but also decide how to handle it. In this case the singularity is the south pole, whose latitude is determined, but longitude is not. When you have it, you should add the -180,180 range to envelope longitudes (or I'm missing something)? Cheers Andrea ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
