Add new Bedford Av entrance and corresponding concourses to the Nostrand Av (IND Fulton St) subway station.
What did you base this edit on? Do you have some sort of map?
Published using OSMCha: https://osmcha.org/changesets/98936849
Thanks for taking the time to look at this! I was in this station and mezzanine earlier today.
The subway entrances were based on satellite view, the entrance was built where there used to be emergency exits or grates (as seen from satellite view.)
What I'm less sure about is the mezzanine, the shape is approximated based on the positioning of the grates on south side of the street visible from the concourse below (for example, there is a set of 3 grates right at where the mezzanine splits up), and referencing videos like: https://www.youtube.com/watch?v=jVtSYm9yabs. I read https://help.openstreetmap.org/questions/6213/what-is-the-minimal-expected-accuracy-of-maps, but I'm not sure if this level of approximation is allowed or adding the mezzanine was a necessary addition in the first place.
Hi pixely, welcome & thanks for your work. I'm not wondering so much about the exact geometry but about tagging this underground subway station as a building. That's something I haven't seen before. Is this an established tagging practice?
I'm not sure what the appropriate tag would be for a subway entrance and concourse, so I selected "Subway Station". I noticed that nearby stations (like Franklin Av station 1 block west, and Atlantic Avenue-Barclays Center) use "Train Station Building" but I did not see that as an option in the editor.
The Franklin Av station is tagged as a building because it's above ground. Atlantic really isn't but it still has one old "head house" at https://www.openstreetmap.org/way/248165091 which is mapped as a building. (It might make sense to map the above-ground portion of the entrance at https://www.openstreetmap.org/node/1956618005 as a building too.)
As far as I know there really isn't yet an official standard for how to map the areas of a subway stop between the entrances and the platforms. Plenty of people have made attempts, but they don't all seem to agree on how. But the general rule is: if it's not above ground, it's not a building.
You've really jumped into the thick of it by starting off with mapping the subways! They definitely need a lot of work, but the methods for mapping them are still unstandardized and under development. There are always new proposals for how to deal with this stuff, and I'm not always up to speed, but I'm happy to talk about it if you have any other questions.
Good luck, J
https://wiki.openstreetmap.org/wiki/Railway_stations documents some of the aspects of mapping subway stations.
Unfortunately the wiki's not too much help regarding subway station mapping, at least not at the moment. It simply says "currently there are a number of proposals relating to subterranean stations" but doesn't give any concrete information on tags and best practices. At some point, hopefully, the community will coalesce behind a standard.
I've been mapping the excavated underground areas of subway stations as `building=train_station` + `location=underground`. There are a few examples elsewhere in the world of this tagging scheme being used (I'd link an Overpass query here but my home internet is broken right now and I'm on my phone). The default renderer seems to support this tagging scheme elegantly, having them show up underneath the surface-level streets and buildings.
My understanding is that these are train station buildings that happen to be underground, hence this tagging scheme. I'm curious to hear others' opinions and rationale though.
Here's a more complete example that I've worked on in San Francisco: https://openlevelup.net/#19/37.78432/-122.40773
Once the data loads, try exploring the basement levels by clicking on the negative numbers on the right sidebar. The underground station building outline shows up based on the maximum and minimum levels given in its tags. The station is further subdivided into indoor areas, rooms, and railway platforms.
Some train stations have buildings, and some don't. I've always understood that underground space does not equal a building, but these standards change over time. (The wiki mentions building=cellar + location=underground, for instance.)
If it's demonstrably good for the map to call subway stations underground buildings, I don't have a problem with that. But it would be great to have these methods documented somewhere. If the wiki's too fraught maybe consider a diary entry?
(Sorry to be spamming you with all this pixely ... public transit mapping is "can:contents=worms".)
I went ahead and changed the area mapped here to `indoor=area` because it doesn't seem to represent the entire underground station. I encourage pixely to map the indoor areas corresponding to the other entrances, and to connect the indoor areas to both the upper- and lower-level platforms however they're connected IRL.
A diary entry seems like a good idea. This isn't the first time I've run into tagging disputes on underground stations. Perhaps documenting it will alleviate some confusion and provide a place to discuss and come to a consensus. I'll write one up soon.
I guess since underground "buliding" mapping is unclear, at least we should be mapping walkways to connect things. Probably especially the long ones further away from the actual stations?
Diary entry here: https://www.openstreetmap.org/user/clay_c/diary/395781
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