[Tagging] Feature Proposal - Voting - Metro Mapping

Ilya Zverev ilya at zverev.info
Fri Nov 10 15:48:06 UTC 2017

Martin Koppenhoefer wrote:
> sorry for asking so late, but why should we deprecate mapping subway stations with a relation or a way and insist on nodes? There are already a significant number of stations mapped like this. I would also not write: "The location of the node is irrelevant." or "There is nothing wrong with putting the node near its entrance: it does not affect routing or anything else." but explain more careful where the node should be put, and what it's meant to know (if it wouldn't affect anything we could also not put it, no?).

Subway stations are mostly underground and, unlike overground stations, are a set of disjoint facilities joined by tunnels, invisible on satellite imagery. Nobody except the architect or a security employee can draw a polygon for underground station properly: you don't usually see service rooms or know how wide the tunnel is, and very few people, maybe less than ten in the whole world, would actually go with a laser ruler to measure angles and distances required for mapping an underground facility.

Then, having stations as polygons or multipolygons makes managing a stop_area and route relations much harder to manage. I don't know about iD, but in JOSM it takes several clicks to select a multipolygon. And with sparse editing techniques, you can't be sure whether a station exists if it's drawn with a multipolygon.

536 subway stations in the world are mapped with polygons, which makes for 4,5% of all metro stations. 421 of these (78%) also have building=* tags. I consider tagging a building a station a bad practice, for the building can have e.g. a different name or a different operator. Sharing an object between features is frowned upon, and I don't want to encourage this practice by allowing station tags on a polygon.



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