This is a guest post by Alex Iannicelli and Yunzhi Li from Facebook.

Throughout the United States there are many places where railways intersect with highways to create “Level Crossings”. Representing these intersections in OSM correctly can improve renderings and routing algorithms. To help improve these intersections we recently created a MapRoulette challenge to verify level_crossing tagging correctness on railways in the US. If you are interested in helping to improve level crossings in the US, you can find this challenge here: https://maproulette.org/browse/challenges/17664. We’ve included detailed instructions in the challenge and most issues should be straightforward to address.

A level crossing in Brisbane, Australia. Source: Ash Kyd on Flickr

The challenge was generated using Atlas Checks, which is a quality assurance tool for map features. You can learn more about it here: https://github.com/osmlab/atlas-checks. The level crossing atlas check looks for nine different issues that we see regularly having to do with these level crossings. The following is a brief description of the issues that are flagged by this check:

  1. When an area or way contain railway=level_crossing tag.
  2. When a car navigable highway crosses a railway on the same layer and the intersection node contains railway=crossing Instead of railway=level_crossing.
  3. When a car navigable highway crosses a railway on the same layer and the intersection node does not contain railway tag.
  4. When a node contains railway=level_crossing but there are no car navigable highways that contain this node.
  5. When a node contains railway=level_crossing but there are no railways that contain this node.
  6. When a node contains railway=level_crossing but there are no railway and car navigable ways on the same layer.
  7. When a car navigable highway crosses a railway on the same layer and an intersection node is missing.
  8. When a node contains railway=level_crossing but there are only pedestrian highways at this intersection.
  9. When a node contains railway=level_crossing but there are only bicycle ways at this intersection.

If you’d like to learn more about the Atlas Check that was used to create the challenge we invite you to read about it here: https://github.com/osmlab/atlas-checks/blob/dev/docs/checks/levelCrossingOnRailwayCheck.md

We look forward to any feedback!

Please let us know if there are any questions or suggestions about the challenge or If you have feedback about Atlas Checks or ideas for new validations that you’d like to see added to Atlas Checks by getting in touch with us on slack or through OSM.

Would you like to promote your Challenge on the MapRoulette blog? Send us an email!