On 2 October 2010 05:28, Michał Borsuk michal.bor...@gmail.com wrote:
2010/10/1 Jo winfi...@gmail.com
[...] I'm pretty sure that if one gets the PT companies to share their
data, it's not going to be in there with child relations.
Usually (e.g. HaFas) timetables consist of a number of routes, and those
are very detailed, each direction is mapped separately, and e.g. if a bus
ends its day not at the terminus, then it's yet another route. This
approach is easier to store in a database, but is in my opinion that one
step too detailed for humans to manage in OSM. It would apparently make
sense to make a collection named line 123, and store child routes withing
that collection, but as of today there is no efficient way to deal with
this.
Transmodel breaks public transport routes down into the following:
Line: (a service with a single service number - 13, X3, 200 etc)
Route: A physical path through the network (on tarmac or rails normally)
Service Pattern: A sequence of Stop Points called at in turn with an
associated Route (a line will normally have 2 or more Service Patterns)
Timing Pattern: A set of timing for a particular Service Pattern (service
patterns can have multiple timing patterns)
Vehicle Journey: A departure time and set of dates/days with an assoicated
Timing Pattern (A timing pattern can have mulutiple Vehicle Journeys).
There is also a way of grouping Service Patterns into Directions and methods
to deal with trains that divide and join (ie the front and back are
eventually heading for different places). Many other tedious exceptions can
also be modeled.
More here for brave people
http://en.wikipedia.org/wiki/Transmodel
Personally I suggest that we limit the transit information in OSM to the
minimum and leave the detail in GTFS. Personally I would like someone to
create a bus-map application using OSM together with GTFS schedules - doing
that would remove a lot of the pressure to model public transport in OSM.
I do suggest that we add bus stops to OSM as they are physical features, the
rest to my mind belongs in the schedules file. To achieve that we would need
some solid mapping from the bus stops in GTFS to their features in OSM.
There are many GTFS files available already here:
http://www.gtfs-data-exchange.com/agencies
Regards,
Peter
--
Best regards, mit freundlichen Grüssen, meilleurs sentiments, Pozdrowienia,
Michał Borsuk
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