All, Geometry validity with polygons is really hard. The only solution at Mapbox we found to fix this properly for Vector Tiles that we create was to modify an existing algorithm to solve all the potential problems of geometry validity. The result of this is https://github.com/mapbox/wagyu/ which we use in our Vector Tile creation scripts now. Unfortunately it doesn't have great performance when using extremely high numbers of points in polygons. However, for vector tiles this typically should not be needed if simplification is done prior to VT creation. If there is supported needed around this problem I am more then willing to lend my expertise.
Thanks, Blake Thompson On Wed, Feb 14, 2018 at 10:53 AM, Rahkonen Jukka (MML) < jukka.rahko...@maanmittauslaitos.fi> wrote: > Even Rouault wrote: > > > Perhaps you could play with the SIMPLIFICATION and > SIMPLIFICATION_MAX_ZOOM options ? > Sure, as I wrote I admit that my test did not make much sense, but trying > things before reading the manual sometimes reveals something interesting. > > > Perhaps you should also use an already simplified layer for the lowest > zoom level (see the CONF option) > For sure yes, coordinate space of 4096x4096 is far too small for this > dataset. > > > Are you sure you get polygons with less than 4 points ? Normally they > should be discarded. > Quite sure yes by looking at what the ST_IsValidReason from the SQLite > dialect prints > ST_IsValidReason(geometry) (String) = Invalid: Toxic Geometry ... too few > points > > There are other variants of invalid geometries and actually a few valid as > well. Here is one example with an invalid component > > MULTIPOLYGON (((516384 6815744,516384 6815744,532768 6815744,516384 > 6815744)), > ((516384 6815744,516384 6815744)),((516384 6815744,516384 6815744))) > > My zero tile is here http://www.latuviitta.org/downloads/0.pbf > > -Jukka Rahkonen- > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/gdal-dev
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