Hi Marco, Am 29.10.2019 um 10:49 schrieb Marco: > Buffer 0 on INVALID geometries IMHO can lead to good results depending > on the nature of the invalidity. To my experience repeating points, > wrong coordinate ordering and holes touching outer shells in one point > are being repaired well without data loss.
I'm sorry to say that the side effects are worse. Maybe the implementation of QGIS is wrong, but try the example below. > Please enlighten me with a few links to the tons of tests on the web > showing that buffer 0 is destroying data. My Google skills are not up to it. I've just updated the example I'm normally showing students with an actual thematic, I'm calling in "wronxit": [1] Try to "buffer(geom, 0)" it in QGIS... This problem isn't constructed (well, this geojson is of course), but I'm got lots of self-intersecting polygons from different sources all the time. "Buffer 0" is destructive here and since many self-intersections are damn small, most users simply don't see them. "Fix Geometries" gives the correct result. Best regards, Tobias references: [1] https://gist.github.com/tobwen/39bc3562d1cb957cbaf4305ef53f77df _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
