OpenStreetMap
In Vancouver, we have a mass transit system known as the SkyTrain. It runs almost entirely above ground with the exception of a few blocks in Downtown Vancouver. On OSM it’s stations are tagged with “subway=yes” and the line itself is tagged “railway=subway” and “bridge=yes”.
This recently resulted in a maps.me user being confused, probably because the application called it a subway when I don’t think anyone here would typically call it that because it hardly runs underground at all.
So that made me wonder, where is the error here:
- Does our schema need fixing? Should we use “railway=rapid_transit” instead of “railway=subway”?
- Should map.me and other map consumers just “know” that “railway=subway” and “bridge=yes” is not actually a subway and display accordingly?
- Should we just use “railway=light_rail” even though it doesn’t really fit the category of light rail?
- Should users just live with the fact that we call all forms of rapid transit a “subway”?
Discussion
Comment from BushmanK on 23 June 2016 at 00:39
Let’s start from Railway page of OSM Wiki For urban passenger rail service you have three choices (except monorail):
subway,tram,light_rail. Forsubway, corresponding page says: > The system should be completely separated from other traffic, usually underground So, it doesn’t fit SkyTrain, since it is separated, but rarely underground.For
tram, definition sounds like this: > This tag can be used for tracks which are mainly or exclusively used for trams, or where tram tracks are laid within a normal road open to all traffic, often called street running Definition is a kind of broad, but tram systems rarely have absolutely no portions shared with common road traffic, while SkyTrain is completely separated from it.For
light_rail, definition requires the following: > A mode of urban transportation utilizing predominantly reserved but not necessarily grade-separated rights-of-way. Electrically propelled rail vehicles operate singly or in trains. Sky train has reserved and grade-separated ways.While there are words about fuzzy definitions, SkyTrain doesn’t seem to be a borderline case, where it’s hard to decide. It does have all main features of light rail, even at higher grade than Trimet MAX in Portland, Oregon (which is always referred as a light rail).
So, I have no idea why anyone would tag SkyTrain as subway (you can probably trace it back to original authors in object history and ask them).
Answering your question about navigation apps, since OSM has a rule “don’t map for navigator”, you shouldn’t really care about it, you should care about reflecting real world features with corresponding geometry and tags.
Comment from BushmanK on 23 June 2016 at 00:41
Ups, sorry, messed up quotes a bit (damn Markdown). Last sentence in every quote is mine.
Comment from Alan Trick on 23 June 2016 at 02:16
I think what makes SkyTrain not really light rail is that its entirely separated from everything else. For example, Trimet MAX appears to have road crossings, but SkyTrain never does. Unlike Trimet MAX, SkyTrain is completely separated from any pedestrian/vehicle areas. This means that SkyTrain vehicles can move much faster without having to risk an accidental collision with a stray child or a drunk driver.
I think that’s what classifies SkyTrain as rapid transit as opposed to light rail. Subway is also a form of rapid transit, albeit underground. The problem is there’s know current categorization for rapid transit that is not a subway.
Comment from winnewoerp on 24 June 2016 at 18:41
It’s true that “subway” for a mass transit system running more than 90% above ground is confusing. So I agree to Alan Trick. So, we don’t have to see “subway” as an underground system in OSM.
Rail transit basically has four hierarchical levels: heavy rail for long distance, regional, and suburban rail services running on “normal” rail infrastructure (railway=rail), segregated rapid transit underground or above ground (railway=subway), light rail for modern tram systems or a mix between subway and tramway, e.g. U-Stadtbahn systems in Germany, prémétro in Belgium or many systems in Northern America (railway=light_rail), and real tramways resp. streetcars, not segregated from road traffic and often even running on the same lanes as road traffic (railway=tram).
SkyTrain clearly belongs to the “subway” category.
It is an important issue within OSM, though. In Hamburg (Germany) for example, I still do not agree that our suburban rail network is mapped as rail=light_rail (same in Berlin). Technically, it is heavy rail, even though almost the whole network is powered by third rail instead of overhead wire. In some parts it even uses the same tracks as regional and freight rail. Well, the community decided that it has to be light_rail, although I changed all the network to railway=rail once.
Comment from pnorman on 25 June 2016 at 22:40
The SkyTrain is a
railway=subwayas defined in OSM. As the text usually underground indicates, mostrailway=subwaysystems are underground, but this one isn’t for much of the length.The Evergreen line was originally planned to be light rail, but was changed to use the same technology as Skytrain. There are also tentative plans for light rail sometime in Surrey
Comment from Alan Trick on 26 June 2016 at 05:02
It seems to me, at least as far as the English language goes, a “subway” is an underground rapid transit system. The description for
railway=subwayon the OSM wiki matches the category of “rapid transit” much more than it does a “subway”. So what I’m asking is: should OSM consumers just know thatrailway=subwaydoes not necessarily correspond to what would normally be labelled a subway unless it also has thetunnel=yestag?Comment from Alan Trick on 26 June 2016 at 05:24
And if we’re adding international examples. The LRT in Manila which has “light rail” right in its name, even though it is very similar to the SkyTrain and doesn’t fit the OSM wiki’s definition of light rail.