[Tagging] Questions about public transport tagging
ipswichmapper at tutanota.com
ipswichmapper at tutanota.com
Fri Nov 13 22:50:50 UTC 2020
Hello, I have quite a few questions about Public Transport related tagging in Openstreetmap.
My first question is about the "interval:conditional" & "opening_hours" tag for bus routes. The "Bus Route" page on the OSM wiki mentions this tag, but the train route or "public transport" route page does not mention this tag at all. So I wanted to ask, is this tag discouraged?
The disadvantage of this tag, obviously, is that it is quite difficult to maintain. However, I think it is possible. My method would be to make a table which contains all the public transport route relations in an area, and add a column for "last checked". This would display the last date that this public transport route was checked. Regular mappers can do a check of a bunch of public transport routes every few months to see if the opening_hours or interval:conditional has changed. (I plan on including this on a guide to mapping public transport routes that I will be making).
Here is the table for Ipswich:
Note currently, this is not formatted how I described. The reason for this is because not every bus routes has been added, so instead of having a "last checked" column, there are four columns ("interval", "interval:conditional", "duration", "opening_hours"). This is because some of the unfinished routes still don't have these tags.
Second question is about mapping train route stops. If I understand correctly, you are meant to add the platform at which people wait with role "platform" as well as the stop position of the train with role "stop".
I see issue with this. Firstly, none of this is clarified on the wiki under train routes. Secondly, what if you don't know what platform the train will leave from? What if there is no platform? In the UK this isn't a problem as all train stations have platforms. However, in other countries, in rural areas, train stations may not have any built up platform, you just wait by the side of the railway.
Secondly, why do you have to map stops and not platforms? Again, if the train goes at different platforms, then the stop position will also be different. You may not know what the stop position is, in which case you chose a random point on the railroad. Instead, it would be much better if you could just mark the "station" as a member of the relation. However, there is no "station" role, so adding a station creates a role verification problem.
Last question is about "combining intervals". This is something that, if needed, can be asked about in another thread (as it needs more discussion). In many cases, multiple bus routes go down the same path for a significant section of their journey, and split near the end of their journey. An example of this is route 66 & route 66A in Ipswich. 
For most of their journey, these buses have the same route. Combined, their interval is "every 20 minutes". The interval of 66A is every hour. The 66 has a 20 minute interval, then a 40 minute one, then a 20 min one, etc.
If these were mapped separately, you a routing software wouldn't be able to compute that the interval is 20 minutes. So how can this be fixed?
The solution I can think of is to map a separate relation called ("66/66A") which is the combined route and give it a interval of 20 minutes. However, I'm pretty sure some tags would be needed to be made for this, because otherwise it breaks the ground rule (as there is no bus called "66/66A" in real life).
Another interesting idea was suggested in this Reddit post:
That is that roads with multiple bus routes can be tagged with the bus route, instead of the other way route (to cut down on repetition).
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