Implementing the Spilhaus projection I learned how the images in the documentation are generated, like the one in https://proj.org/en/latest/operations/projections/spilhaus.html if you have a look at docs/plot/plotdefs.json you will see that the workaround is to not plot very long lines, that are usually crossing from one border of the projection to another.
On Sat, 8 Mar 2025 at 22:03, Nyall Dawson <[email protected]> wrote: > On Sun, 9 Mar 2025 at 04:06, Javier Jimenez Shaw <[email protected]> > wrote: > > > > If you mean in a generic way, I think the answer is no. > > Each projection has its own peculiarities and behaviours. Spilhaus (by > the way, not yet in PROJ, but coming in 9.6.0) is a good example. > > Testing Spilhaus in QGIS was actually the motivation for this > question. It works fine for rasters, but for vectors there's extreme > artifacts caused by rendering features crossing the boundaries of this > projection. > > > > > "... latitude (or projected x coordinate) " Do you mean longitude? See > that the longitude you are looking for may depend on the latitude. > > 🤦 of course! (*although for the above mentioned Spilhaus projection I > guess we'd need something more complex than a single line longitude > line anyway!) > > Nyall > > > > > > > On Sat, 8 Mar 2025 at 07:30, Nyall Dawson via PROJ <[email protected]> > wrote: > >> > >> Hi list, > >> > >> A question: given an arbitrary projection/CRS, is it possible to > determine the latitude (or projected x coordinate) at which features would > need to be "cut" in order to avoid artifacts when those features wrap > around the projection extremes. > >> > >> Eg if it was EPSG:4326, we'd need to cut the features at +/- 180. But > if it's another projection... say mercator or spilhaus or ... is there any > way to reliably determine this cutting line? > >> > >> Nyall > >> > >> _______________________________________________ > >> PROJ mailing list > >> [email protected] > >> https://lists.osgeo.org/mailman/listinfo/proj >
_______________________________________________ PROJ mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/proj
