search

mapbox / tippecanoe

Build vector tilesets from large collections of GeoJSON features.
BSD 2-Clause "Simplified" License
2.64k stars 426 forks source link

Small rendering bug when using --detect-shared-borders #846

Open malwoodsantoro opened 4 years ago

malwoodsantoro commented 4 years ago

Data: greenland.geojson.zip

Adding raw GeoJSON to the map (no rendering issues): greenland-geojson

Running data through Tippecanoe with --detect-shared-borders. Notice white line in the 2/1/1 tile: greenland-detect-shared-borders

Screen Shot 2020-02-18 at 11 21 43 AM

tippecanoe --output=greenland.mbtiles --minimum-zoom=0 --maximum-zoom=5 --buffer=2 --low-detail=10 --full-detail=10 --drop-smallest-as-needed --no-feature-limit --detect-shared-borders greenland.geojson

Running data through Tippecanoe without --detect-shared-borders. No white line in the 2/1/1 tile:

greenland-no-detect-shared-borders

tippecanoe --output=greenland.mbtiles --minimum-zoom=0 --maximum-zoom=5 --buffer=2 --low-detail=10 --full-detail=10 --drop-smallest-as-needed --no-feature-limit greenland.geojson

e-n-f commented 4 years ago

Thanks! I'll take a look.

e-n-f commented 4 years ago

I can reproduce the rendering glitch at certain zoom levels (zoom 2.98 here):

Screen Shot 2020-02-18 at 12 53 08 PM

I think this is a triangulation or rendering bug in Mapbox GL, not a bug in Tippecanoe. As you can see in the screenshot, the missing row of pixels does not have an outline like the coastline does, indicating that it is part of the interior of the polygon, which is the renderer's responsibility to fill, not part of the edge, which is the tile encoder's responsibility to provide.

tomkdgun commented 2 years ago

I think this is a triangulation or rendering bug in Mapbox GL, not a bug in Tippecanoe. ...

@ericfischer @malwoodsantoro What is the status of this issue ?