Hi, today I'm getting crazy against the stereophic projection and the niceties of the antarctic area. One is that it breaks totally optimized data loading inside the renderer when there is data that is in 4326 and it needs to be projected towards stereographics (3031).
Usually we do compute the map area, we do reproject the envelope back to the original data crs, and issue a bbox query against the data, to avoid having to load data we don't need. The reprojection of the envelope is made sampling the map area envelope perimeter. In the case of a map area in stereographic, the perimeter happens to me more or less at the same latitude (for an example of steregraphic projection, see http://jira.codehaus.org/secure/attachment/27832/wms-1.6.x.png, the image is flipped upside down, but it should give you the idea). This means the bbox we use for data querying is wrong, because it amounts to a donut with a big hole if you look at it in the map linked above: it does not contain the actual data! To get the actual envelope in lat lon, the center point of the envelope would have been to be sampled too... (in this case...) Now, I'm wondering, besides extending point sampling inside the original bbox (instead of using only the perimeter) do we have any smarter method? Even sampling inside the bbox we could loose part of the actual map area in 4326 if sampling did not happen to catch the pole... 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
