How about a step back for a second here... What is the stop_position
intended for? Who is it intended to help or inform? A bit of context
would help to rank the possibilities.
I remain by my earlier standpoint that a stop_position is too much
detail for a route as it is too variable to be useful. Trains on the
same route will be longer or shorter, and will use different tracks and
different platforms from time to time. What stays constant when
considering the route is the station itself, so this would be the right
entity to make part of the route.
--colin
On 2017-05-12 17:45, Bjoern Hassler wrote:
> Hi Michael,
>
> that's very helpful, thanks. I'll implement the ref as well as the ordering.
> I'll also add this to the English wiki pages where needed. I'll have a look
> at the DE page as well.
>
> Examples for nodes as requested. Stop_position at: - End of platform (middle
> of line) node 13328915
> - End of platform (end of line) node 20955753
> - Middle of platform node 1620401529
>
> (Disclaimer: I was just adding tags for 13328915, but I'll fix this shortly
> to be in the center of the platform. IMHO that is the convention that does
> make sense from a passengers perspective, but yes, it doesn't address Colin's
> comments about physical stop train positions from the drivers perspective.)
>
> Many thanks,
> Bjoern
>
> On 12 May 2017 at 15:48, Michael Reichert <naka...@gmx.net> wrote:
>
>> Hi Bjoern,
>>
>> Am 2017-05-10 um 18:59 schrieb Bjoern Hassler:
>>> In an osm:relation:route
>>> <https://wiki.openstreetmap.org/wiki/relation:route [1]> (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?
>>
>> Stop positions can have a tag ref=* or local_ref=* giving the track
>> number which is signed on the platform. The platform has ref=*, too. The
>> ref tag of the platform often contains multiple numbers because many
>> platforms have to edges, i.e. ref=2;3 or even worse: ref=2a;2b;2;3a;3b;3
>> (if the track can be occupied by two trains behind each other at the
>> same time - very common at busy stations).
>>
>> If you don't want to parse ref=*/local_ref=* and route relations are
>> properly mapped, you can check which route relations reference a
>> platform. If a route relation contains both platforms and stop
>> positions, the next member of a relation after a stop position node is
>> should be the platform.
>>
>> I think that both variants provide better results than simple snapping
>> on the next edge in your pedestrian routing graph (if platforms are in
>> your routing graph). There are cases in reality where a railway track
>> has platforms on both sides but you can or must leave the train only to
>> one direction.
>>
>>> 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?
>>
>> From my point of view this is wrong mapping. (In Germany mainly done by
>> user rayquaza) To give a correct answer, you should give some examples
>> (node IDs).
>>
>> Best regards
>>
>> Michael
>>
>> --
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>> ausgenommen)
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>>
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Links:
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