On Thu, 2 Jul 2020 at 01:12, Martin Davis <mtncl...@gmail.com> wrote: > > On Tue, Jun 30, 2020 at 10:42 PM Nyall Dawson <nyall.daw...@gmail.com> wrote: >> >> It's inspired by this question: >> https://gis.stackexchange.com/questions/365901/finding-longest-straight-line-within-polygon-in-qgis >> The routine is used for calculations like "what's the optimal >> placement for a airplane runway" in this polygon. > > > Well that's pretty cool! The diagrams from QGIS are very nice. They don't > seem to mention performance - I assume it's not very fast using their > approach.
Yeah, it's definitely not going to be fast! The approach used in the answer isn't actually correct either -- you can see in the illustrations that there's longer possible lines. That's due to the use of the "densified" vertices approach, where it's better (and faster) to use the original polygon + ring vertices only instead. But the general approach is fundamentally similar. > I'm continuing to think about the best way to optimize intersecting a line > with an arbitrary polygon (fully general, so can contain holes). Am zeroing > in on a solution, but don't have it running yet. It will be interesting to > see how much faster it is. Do you think this algorithm is a candidate for inclusion in JTS/GEOS itself? Nyall > _______________________________________________ > geos-devel mailing list > geos-devel@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/geos-devel _______________________________________________ geos-devel mailing list geos-devel@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/geos-devel
