[Talk-transit] Tram routing

Gerrit Lammert osm at 00l.de
Thu Jan 22 19:27:51 GMT 2009

Hello Frankie.

Frankie Roberto wrote:
 > On Wed, Jan 21, 2009 at 8:19 PM, <osm at 00l.de> wrote:
 > That does seem to be the case. It may be because, on that particular 
 > the tram runs in a grade-separated section of the road that cars and 
 > road traffic can't use. However, I'm guessing that in that case, the ways
 > should be side by side rather than sharing nodes?

I don't have a strong opinion regarding that, but to me this seems to be 
the most practical solution, yes. I would split an otherwise homogenous 
way whenever there is no other way to map a situation properly or there 
is some physical barrier. This may be a "guard rail" 
(http://dict.leo.org/ende?lp=ende&lang=de&search=leitplanke) or 
dedicated rails between lanes as well as some "island" on the street 
allowing people to board trams/buses.

 >> - I think your relation for tram routes is already often used (at least
 >> here in germany). I also don't see why we should use an other convention
 >> than with trains and busses.
 > Good. I might go about adding it to the wiki page on relations then.

It never occured to me that there might not be such a page. It was so 
natural to me to do it like this. ;-)

 >> - You could add the tram stops to the routes' relations.
 > Are they not already part of the relation by virtue of being included 
 > the ways? Or are there some advantages to having them included 
separately as
 > nodes? In which case, do they need a specific role? (I'm a bit new to
 > relations).

Well, in theory one could just implicitly add all stops along the way. 
This might work well for trams. But for busses, there are situations 
where a stop alongside the route is not served by a given bus line. 
Might be its an express route or there is a crossing with seperate stops 
  on all for corners to serve different lines and one line passes two as 
it takes a turn.

    | |b
a__| |____
___  _____
    | |  c
   d| |

To be coherent I would also add the served stops in train/tram routes.

 >> - I'd like if you'd try/play around with my proposed scheme to tag the
 >> stops. This would mean here:
 >> For each stop add the node/way next to the rails where people wait 
for the
 >> tram and tag it with highway=platform;shelter=yes/no;...
 >> Than create a relation combining all tram_stops and platforms of the 
 >> station with type=site;site=stop_area;name=YourName;...
 > Sounds interesting, I'll give it a go. Most the of tram stops in 
 > don't have shelters, but some do... Could also include nodes for ticket
 > machines, but not sure I'll be able to get accurate enough positions for
 > those...

Thats the idea. Bind everything with the stop_area relation that can be 
attributed to that stop. Ticket machine is a good example.
I myself usually am fine with just tagging one node where the stop sign 
approximatly is situated and adding everything nearvy (shelter, ticket 
maschine, timetable...). But for huge stations like train stations one 
should tag the whole actual platform as highway=platform (or 
amenity=platform?) and have seperate nodes to mark the position of the 
shelter or ticket maschine...

 > Ah, and I've just realised that some of the stops use island
 > platforms, which I presume it doesn't make sense to map unless there's
 > a way for each track...

yes, see above.

 > I also need to do some more investigation around the Piccadilly 
Gardens area
 > - there are two tracks which go slightly different routes, which I 
think are
 > used for different directions, in which case, might oneway=yes apply?

I guess so. Thats how I would do it anyways.


PS: Sorry for this incomplete discussion. I always forget to add the 
mailing list when hitting reply. Could someone modify the list's 
settings so that the mailing lists address is the default reply-to?

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