[Tagging] rail routes: how are platforms and stops associated (rail question 2)

[Tijmen Stam]

On 10-05-17 18:59, Bjoern Hassler wrote:
> Hello again,
>
> In an  osm:relation:route
> <https://wiki.openstreetmap.org/wiki/relation:route> (type=route,
> route=train/...), you have both platforms and stop positions. How is a
> particular platform associated with a stop that serves it?
>
> E.g. for public transport routing, you'd walk (highway=footway) to a
> platform (public_transport=platform), at which point you'd change to a
> train stopping at a stop (public_transport=stop_position). How would the
> routing algorithm know that the platform is associated with the stop?
>
> Is there an existing mechanism or convention, e.g. a tag on the platform
> that indicates the stop, or both tagged with the same name or similar?
>
> Thanks!
> Bjoern
>
> PS I've noticed that sometimes the stop position is at the far end of a
> platform (i.e. the two stop positions are at opposite ends of the
> station). Maybe that's so that an association can be made?

Answering your grand question:

As I interpret the wiki, it is the route-relation that ties together the 
stop_position with the platform, by including them as a pair per "halt".

Imagine the "renderer" is a transit simulator that simulates a journey 
from your home to somewhere via "Green line" that stops on track 1 
(platform A), then the route relation of the green line contains both 
the stop_position (a node on track 1) and the platform (platform A).
It would then plot a walking route to platform A, then transfers you 
into the train (on track 1) and along the route.

I know of people who use a stop_area-relation for each 
stop_position/platform pair, which then could be used to tie 
stop_position and platform together, but that is not how I interpret the 
wiki.
I use one stop_area for a whole station.

Tijmen/IIVQ