Markus Metz wrote: > How about reversing the current policy? Restrict both raster and vector > maps to the 180 degree lon and 90 degree lat limit, that avoids > duplicate features within a map. Allow the region to be set anywhere > between -360 and 360 lon but restrict the width of the computational > region to 360 degrees lon to avoid duplicates.
That is problematic for computations which use a window (e.g. r.neighbors, r.proj, r.mfilter etc) on a whole-earth map. For that, you need 360 degrees plus the width of the window. [The same issue applies at the poles, but people don't normally care about the poles if they're working in lat/lon.] > Wrap map contents to the > current computational region if any map contents exist that fall into > the computational region. This would allow traversing the datum border > without gaps or breaks, e.g. for raster resampling. The display is not > affected, apart from "zoom to the current computational region". > > I'm afraid you have thought of that possibility before and found flaws > in it. Apart from rewriting a lot of code... AFAICT, the most important case to solve is when the region is set to the Bering strait, and a vector map has Alaska at ~180W and Sibera at ~180E. Some of the data will need a 360-degree shift to obtain the correct relative position. -- Glynn Clements <gl...@gclements.plus.com> _______________________________________________ grass-dev mailing list grass-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-dev