[Talk-transit] [Talk-gb-westmidlands] Bus operator references

Peter Miller peter.miller at itoworld.com
Wed Jul 1 16:18:18 BST 2009


On 1 Jul 2009, at 14:43, Andy Robinson (blackadder-lists) wrote:

> I'm a bit confused by what are the correct bus operator references  
> in west
> mids.
>
> For example, Brian is using NXWM for National Express West Midlands  
> which
> would seem logical, however on the Centro website if I check at the  
> bottom
> of a route number page I find that WMT is still referenced on all the
> timetables and operator code given as WMT not NXWM.

Do be aware that two or more bus operators can share a route, often  
with one running during the busy periods as a commercial service and  
another being paid under contract to run services at quieter times  
(evenings and weekends for example). Also be aware that you are using  
the term 'route' to cover all the roads that a service with a  
particular service number uses. In Transmodel it is refined a bit with  
a number of different terms. It would make the professional community  
very happy, and might work better in the longer term for OSM to  
reflect on their modelling and terminology for a few minutes. In the  
following text I will use Capitalised words for Transmodel concepts.

In Transmodel a Line is a thing with a pubic facing code (ie 11C, 71,  
105 etc) - so what you call a route is what Transmodel calls a Line.

Transmodel uses the term Route to mean a unique ambiguous path through  
the transport infrastructure (road or rail) taken in whole or part by  
a vehicle operating on a Line. There will normally be two or more  
Routes per Line (in opposite directions for starters and then possibly  
various detours). At some point we are going to want this information  
in addition to the correct collected data in the route relations.

It then defines a Service Pattern as a unique sequence of Stop Points  
that a vehicle calls at while it goes along a Route (it may not stop  
at all Stop Points it passes on the route). There can be more that one  
Service Pattern for one Route, normally due to short working.

Timing Patterns are defined giving the interval of time between Stop  
Points and are associated with a Service Pattern. There can be more  
that one Timing Pattern per Service Pattern. In the rush hour more  
time is allowed for completion of the route than during off-peak times.

Vehicle Journeys then run on a Timing Pattern (which have an  
associated Service Pattern and hence Route and Line) at particular  
times. Each Vehicle Journey is associated with an operator (allowing a  
Line to be shared between multiple operators). The Vehicle Journey  
only needs a start time, set of days and data range and Timing Pattern  
and everything else can be worked out from the Timing Pattern and  
associated Service pattern and Line. It is pretty clever general and  
normalises out repetitive data (such as Service Pattern and Route)  
while allowing all situations to be accommodated.

Sorry for the rant / brain-dump, but it is something that I have  
wanted to raise for a while now. It may be useful to use the Route  
relations to mean what Transmodel means by a Route (a unique path  
through the network) and then wrap those Route relations up into a  
Line Relation.

Anyway, something to think about.




Regards,



Peter



>
> Any ideas, I think this crops up with other operators too.
>
> Cheers
>
> Andy
>
>
>
>
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