This collaborative mapping project, introduced by TomTom, aims to improve the quality of the buildings in OpenStreetMap USA by fixing buildings with self-intersecting polygons. By resolving these self-intersections you will provide users with a better visual experience when viewing or incorporating OSM buildings into their applications.
This challenge is recommended for the more experienced mappers due to the complexity of some of the situations you will encounter in the challenge.
Hi there. I don’t think a MapRoulette challenge is the best way to fix this issue here. The first task I tried led me to discover an entire neighborhood full of improperly mapped duplex homes, all mapped as type=multipolygon in the same invalid way.
Perhaps it would be better to just present a map that highlights instances of self-intersecting polygons, and let the community decide how to approach fixing them in each locality.
I “fixed” a few of these but don’t have a good feeling about them. They were buildings which shared a roof and thus two polygons but had been combined to create an invalid multi-polygon. Linguistically they should be combined but of course this is an invalid OSM multi-polygon. I could separate the roof as a separate building and thus delete the multi-polygon but JOSM can no longer delete multi-polygons
Hi @clay_c, This is great feedback and based on your and @MikeN comments I think it best that I disable the challenge and revisit the scope and approach.
Hi @MikeN , Thank you for working some of the tasks in this challenge and for your comments. based on yours and other feedback I have decided to pull the challenge at this time and revisit.
I tried a few. All were 3D building relations that I have a little experience with. You can probably ignore any overlaps where any polygon has a building part tagged. 3D buildings in OSM is super advanced—I would avoid.