Topology errors in 512px tiles widespread for landuse polygons #95
Description
Compared to the 256px tiles I'm seeing many more topology errors and dropped polygons in the 512px tiles. I think this is because after trying to make a polygon "whole" a few times, if we still fail we drop the feature. We need to do a better job to keep the features.
For example, northern California:
http://tangrams.github.io/walkabout-style/#8/40.815/-124.094
512px tiles miss the wilderness areas, but 256px tiles include them:
At zoom 10 around Eureka, California:
http://tangrams.github.io/walkabout-style/#10/40.7353/-123.9306
512px tiles miss the land areas, but 256px tiles include them:
At zoom 9 around San Francisco, California:
http://tangrams.github.io/walkabout-style/#9/37.3865/-121.5486
512px tiles miss the land areas, but 256px tiles include them:
