[OSM-talk] Collecting public transportation time tables

[Peter Miller]

On 17 Dec 2008, at 18:29, Ævar Arnfjörð Bjarmason wrote:

> On Wed, Dec 17, 2008 at 4:47 PM, Adam Schreiber <sadam at clemson.edu>  
> wrote:
>>> I wound be very interested to see the first time that a transport
>>> authority took a person to court for promoting their services but
>>> there may be a first time! I do suggest that this is a different
>>> project from OSM though.
>>
>> Yes, but certainly tied to OSM data though.  It would be very cool if
>> from this other project, people could assemble routes from nodes
>> already tagged as bus/train stops, add time table info for routes
>> already in the OSM DB and set nodes as the appropriate stops.  This
>> would probably need some form of a heavily modified potlache.
>
> I don't see why this needs to be a separate project. We already have
> Key:opening_hours for amenities, why not Tag:highway:bus_stop with
> additional tags that describe when each bus line stops there and a
> relation to map the greater bus route. That should be sufficient
> information to map the transit system and the data wouldn't be spread
> across two independently maintained databases.

I assure you public transport timetables are very complex and one most  
certainly can't implement it as tags to the OSM model. Consider the  
bus service that runs on market days and wednesdays during school  
holidays and stops at some places at a fixed time (a timing point),  
stops at other stops when it gets there (non-timing points), can be  
flagged down on some parts of the route (hail and ride) and will wait  
up to 5 mins for a delayed train at xxx station (connection  
protection). GTFS is the simplest timetable format and even that one  
falls down in complex situations. The complexities go on an on!  
Anyway, if one uses GTFS I believe one gets a trip planner for free  
with Graphserver. This is as simple as it gets and would be a sensible  
starting point. The stops would however be referenced to OSM as would  
the shapes:
http://code.google.com/transit/spec/transit_feed_specification.html

Given that timetables change a lot more frequently than roads and bus  
stops it is actually good practice to separate them.

I am going to ask for a new list. No one else has voted for it but  
there is a good conversation going on and I think it needs a home.


Regards,



Peter