At Facebook, we’ve been releasing our Daylight Map to the public since March of last year. Daylight is a version of OSM that has been quality checked and validated to ensure that the resulting map is safe and of high quality. It is the map data that is used on Facebook maps. Our goal is to make OSM easier and safer to use which will then expand the use of OSM.

When building Daylight, we employ automated validation processes to find bad data. That bad data is then either deleted from the map or corrected in the OSM database. This diary will go over the map validation efforts we’ve made to the map to make Daylight safe to use.

The map validation efforts includes three parts: vandalism and profanity cleanup, relation repair, and Atlas Checks fixes.

Vandalism and Profanity Cleanup

In the last couple years, our engineering team has spent a lot resources to research how we can identify vandalism and profanity more systematically and more accurately. With these improvements to our detection tools, we were able to fix over 360 examples of vandalism and 16 instances of profanity on feature names all over the world.

So what did we flag and how did we make the fixes?

1) We were able to flag features with name values that appear to be spamming the map and are clearly vandalism. Here are some examples where we took action to remove the name value of the features.

Example 1

Example 2

2) Our detection technique also flags Pokemon related edits, particularly Pokemon terms as the name on map features. The action we took was also removing the feature name.

Example 3

3) When profane words are present in the map feature name, the feature will be brought to us for profanity removal.

Example 4

Example 5

Example 6

During cleanup, whenever other data issues occur on the map features flagged for vandalism and profanity, we clean up the data issues as well. For example, in Example 6 above, the map feature involved a dragged node causing the road crossing water features improperly. After fixing the profane name, we submitted a follow-up changeset to address the dragged node.

Example 7

Relation Repair

Another enhancement we’ve made is detection on broken relations. Using the enhancement, we found and repaired over 4,100 relations on OSM. These relations range from simple groups of buildings to complex water features, as below. And often times, the complicated ones had existed on OSM for years due to the difficulty of detection and repair.

Example 8

Atlas Checks Fixes

Other than using improved internal techniques to clean up vandalism and repair relations, we apply an open-source validation tool called Atlas Checks, to detect various data issues, including line crossing waterbodies improperly, name gaps in connected roads, missing relation type, overlapping ways, etc. By utilizing Atlas Checks to detect data issues, and its ability to streamline the detection results to MapRoulette for more systematic fixing, we have submitted more than 7.9K changesets to repair over 122K OSM features.

Atlas Checks Fixes include a large variety of data issues. Here are a couple examples of what we’ve fixed:

Example 9

The water feature was flagged due to overlapping the adjacent highway. We adjusted the water body to avoid the overlap.

Example 10

The highway crossed the river without a bridge, so we split the highway segment out and added proper bridge tags.

Example 11

Name value didn’t continue in the middle road segment while the two segments connected on either end included the same road name. We added the missing name on the segment in between as it is part of a continuous highway.

Since we use MapRoulette as a platform to systematically fix Atlas Checks outputs, it allows us to share these flagged features beyond just our internal team. Most recently, we shared a couple challenges to the OSM community in April and May.

If anyone is interested in supporting these Atlas Check fixes on MapRoulette, please feel free to message us on Slack or email us at osm@fb.com.