I am working with the mbtiles-extracts library: https://github.com/mapbox/mbtiles-extracts. Given an mbtiles file and a geojson, the library extracts mbtiles cutouts of the polygons in the geojson.
Except, it does not work for some geojsons.
As documented in https://github.com/mapbox/mbtiles-extracts/issues/10, it does not work for any polygon present in the following geojson for the mbtiles listed below:
- MBTILES: Pretty much every tileset on https://osmlab.github.io/osm-qa-tiles/historic.html. Can definitely replicate it using for https://s3.amazonaws.com/mapbox/osm-qa-tiles/historic/2008-Q1-qa-tiles.mbtiles
- GEOJSON: https://gist.github.com/arunasank/c98ef28abd51b54579c7609f8ebc1de1
When I debug, I see that:
- This function: https://github.com/mapbox/mbtiles-extracts/blob/master/index.js#L175 returns a falsy value for all the features in the above geojson, resulting in a falsy value here: https://github.com/mapbox/mbtiles-extracts/blob/master/index.js#L58-L62
As suggested by Nikhil V J on https://lists.openstreetmap.org/pipermail/talk-in/2018-November/003211.html, I also tried validating the geojsons, and ensuring that they follow the right hand verification rule, but that did not fix things.
Any help in understanding why these polygons are different from other polygons, or if there's a pattern to these polygons that I am missing, would be really helpful!
