[Talk-transit] Talk-transit Digest, Vol 14, Issue 4

[Shuyan Chen]

Dear Roland

Many thanks for your comments.

Now I see how difficult it is for public transit.Yet I wonder if a public transport graph is more realistic?

>A relation can carry one or all directions of a bus line. In the former case, 
>I recommend to keep both the itinerary (the way the bus physically takes) and 
>the bus stops, usually nodes of type "highway=bus_stop", in the order in which 
>they are served. In the latter case, you often find a big mess on both the 
>itinerary and the bus stops which are left from former times (API 0.5) when 
>there was no defined order on the elements of relations.

Do you think it is possible to get bus stops (includes the origin and destination point) in order in a route through any geometry method?

Regards,

Grace


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Subject: Talk-transit Digest, Vol 14, Issue 4

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>   1. Re: Help: Bus Stop Data Extraction for Bus Routing Service
>      (Roland Olbricht)
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> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 9 Feb 2010 14:28:46 +0100
> From: Roland Olbricht <roland.olbricht at gmx.de>
> Subject: Re: [Talk-transit] Help: Bus Stop Data Extraction for Bus
> Routing Service
> To: "Public transport/transit/shared taxi related topics"
> <talk-transit at openstreetmap.org>
> Message-ID: <201002091428.46198.roland.olbricht at gmx.de>
> Content-Type: Text/Plain;  charset="utf-8"
> 
> Dear Grace,
> 
>> We would like to extract public transport data for public transit routing
>>  service in Sweden.
> 
> This will be a difficult, maybe impossible task at the moment. Public 
> transport data are a complicated matter. Most important for you might be that 
> there is no timetable information in the OSM database. Thus, without a data 
> source for the timetable information, it is not useful for public transport 
> *routing*. Buses running only a few times a week or only on school days can't 
> be discriminated from regular services running every few minutes.
> 
> Also, there is not even a standard for a public transport data model for bus 
> services in OSM. The best possible approach known to me is
> http://wiki.openstreetmap.org/wiki/User:Oxomoa/Public_transport_schema
> But there might be a quasi-standard for Sweden differing from this one, 
> depending on your local community. Please provide some IDs of example 
> relations of the data.
> 
> I'll try to answer to you based on the data model commonly used in Germany 
> (e.g. Wuppertal) or France (e.g. Grenoble).
> 
>> What is the difference between the stop nodes within a relation and the
>>  nodes tagged as ?bus_stop? in highways which are also contained in a
>>  relation?
> [...]
>> Do the stop nodes within a relation merely refer to the passenger waiting
>>  point, whereas, stops in highway contained in a relation represent the
>>  vehicle stopping points?
> 
> In general, the node tagged as "highway=bus_stop" indicates the position of 
> the road sign or shelter and is off the street. If I find such nodes on the 
> street, I move them to their proper position. For the vehicle stop, the node 
> on the street might be tagged as "public_transport=stop_position" but they 
> rarely exist (almost 500,000 bus stops in the database versus 9000 stop 
> positions) or aren't even defined (stop positions in my area depend on the 
> vehicle design, not the served line). The stop areas are introduced to group 
> all the bus stops having the same name.
> 
> A relation can carry one or all directions of a bus line. In the former case, 
> I recommend to keep both the itinerary (the way the bus physically takes) and 
> the bus stops, usually nodes of type "highway=bus_stop", in the order in which 
> they are served. In the latter case, you often find a big mess on both the 
> itinerary and the bus stops which are left from former times (API 0.5) when 
> there was no defined order on the elements of relations.
> 
> Cheers,
> 
> Roland
> 
> 
> 
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> End of Talk-transit Digest, Vol 14, Issue 4
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