In June, TomTom has a MapRoulette challenge to share for United States - Very Close Junctions. In this challenge, tasks were created where nodes between two highways are potentially too close together. As seen the example below, one of the service roads is slightly misaligned and could use an update. In other cases, a location may be outdated and a node needs to be disconnected.
Note that because these are “potential” issues, there may be a higher false positive rate than you’re used to. If there’s any doubt, better to leave it as-is and feel free to mark those tasks as Not an Issue or Already Fixed.
Safe travels to those heading to Madison for SOTM US and hope to see you there!
Thanks for setting up this challenge. Hopefully it helps us finally weed out the remaining cases where the TIGER import introduced these offsets. TIGER always left a tiny segment on the through street that tends to get overlooked, resulting in gaps in route relations and highway classifications.
What’s the minimum distance that you’re using to detect a “very close” junction? I ask because some routers like OSRM are already capable of ignoring slight offsets, so we don’t always need to bend roadways just to avoid confusing guidance instructions. Meanwhile, some dogleg intersections are probably best modeled as staggered intersections in OSM due to lane-level details and other features like crosswalks:
These cases tend to be staggered farther apart, so at a glance your challenge correctly ignores them. Just wondering if there’s any gray area between these two extremes that mappers need to be more careful about.
It’s noted in the MapRoulette challenge description “the distance between junctions is less than 3.7 meters.” Yes, there could be gray area between those two extremes but I’m not immediately aware of any examples from the locations I reviewed.
This is our first iteration of the challenge in the US, so we welcome any feedback. If the distance threshold feels off, or if you run into edge cases or unusual situations, please feel free to share. I’m happy to refine the guidance and incorporate those learnings.
In an initial review, the only gray area I ran into (more source related than distance related) involved ongoing construction. If you run into those situations (especially where street-level imagery is outdated or missing) it’s better to take a cautious approach. In those cases, it’s best to leave things as-is and mark the task as “Can’t Complete.”
Thanks for the question, I definitely appreciate your insights.
Those might be less of a problem in “TIGER-land” though also in the US we have areas which have a high level of detail and blindly solving the challenge might cause some trouble in those areas. Especially if local communities went for keeping an “intersection” staggered, some armchair mapper rather should respect that decisions.
I did not look at any of the challenges here, nor in germany were you run the same challenge. But since streets in the US tend to be wider than in europe I assume you need a threshold larger than the current 3.7 metres.
