Bulgaria - Fix Spiky Buildings

Hello OSM Bulgaria,

I would like to announce a new MapRoulette challenge: Bulgaria - Fix Spiky Buildings . We’ve identified buildings on OpenStreetMap (OSM) with oddly sharp angles. Most building corners are close to 90 degrees, but this challenge focuses on buildings where angles are less than 15 degrees. While some might be real, many are likely incorrect data.

The Task:
Improve OSM data quality by reviewing the identified buildings and see if their shapes need correction.

Important Considerations:

  • Some buildings, especially historical ones, may have unique angles.
  • If unsure, consult the community forum for guidance.
  • The task will lead you to the building itself, not necessarily to the specific “spiky” node. Please zoom in carefully and search for the issue.

Why Fix Spiky Buildings?

Accurate building shapes on OSM benefit everyone! They improve:

  • Data quality for various applications
  • Navigation services
  • Urban planning
  • Emergency response

Have Questions?
Feel free to reply to this message for help, modifying instructions, or suggestions on resources.

Thank you,


Quite a few are already fixed (sometimes mor than a month ago…), with these tags on the change: #UnusualBuildings #FixUnusualBuildings maproulette mpr.lt/c/43054/t/222159750 Can these be filtered out?

Hello @rhhs,

The team will look into it and come back the soonest. thank you for your valuable input as always.


Completed. 31% “Already Fixed”, due to MapRoulette which is also looking for sharp angles in buildings. Probably other Spiky Building challenges have a high percentage “already fixed” too…


Thank you @rhhs!