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tilezen / mapbox-vector-tile

Python package for encoding & decoding Mapbox Vector Tiles
MIT License
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Topology errors in 512px tiles widespread for landuse polygons #95

Open nvkelso opened 6 years ago

nvkelso commented 6 years ago

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:

screen shot 2017-10-20 at 17 15 28 screen shot 2017-10-20 at 17 15 15

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:

screen shot 2017-10-20 at 17 16 46 screen shot 2017-10-20 at 17 16 52

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:

screen shot 2017-10-20 at 17 19 13
nvkelso commented 6 years ago

@zerebubuth after RAWR settles down let's revisit this topology space.

nvkelso commented 6 years ago

Zoom 7 in northern California has a lot of national_forest green areas missing: http://tangrams.github.io/walkabout-style/#7/40.618/-123.876

screen shot 2017-10-20 at 17 24 03 screen shot 2017-10-20 at 17 23 56
zerebubuth commented 6 years ago

Related to #87?

nvkelso commented 6 years ago

Related to #87?

Looks likely. Leaving this issue open until we can prove the link.