[Talk-transit] Public Transport routing

Chris Morley c.morley at gaseq.co.uk
Sat Sep 5 20:47:46 BST 2009


Peter Miller wrote:
> I have been comparing the timetables for October 2009 and August 2009  
> for my home town in Ipswich and I would estimate that 20% of the  
> routes have changed in that time. Some have merged, some have moved  
> operator some have disappeared. That is a lot and I haven't even  
> checked the individual timing for journeys or days of operation. There  
> are some 1.4 million bus journeys in the UK database so if 20% of them  
> disappear randomly every 10 months that is 300,000 changes to spot.

In my area (Chester West and Chester) 19 of the 105 bus services were 
added, withdrawn or had their routes changes in September 2009 alone. 
This is higher than the average but it does illustrate the transient 
nature of routes with the current system in the UK. Unlike Péter 
Connell, I do not think that there are enough enthusiasts prepared to 
do the grunt work of making these changes systematically on a monthly 
basis in every local transport area. It might be fun adding routes, 
but it is difficult to be as motivated on a continuing basis. It's 
true that other OSM data is patchy and sometimes wrong, but is 
generally on a trajectory of continuous improvement. With information 
that is too transient we could eventually be in a situation where the 
quality was getting worse with time.

I think this means that either we should have no routes (option A) or 
if we do they should be automatically updated. This requires local 
authorities to share the information they hold in a comprehensive 
machine-readable format, which we have to hope happens soon. Even 
then, bus routes are maybe better suited to presentation as an 
overlay, with the data in a separate database that also hold timetable 
information. Routes and timetables change together, usually separately 
from roads or geography.

Chris


>>> A) A point where all the world's public transport access points (bus
>>> stops,station etc) are in OSM (but not the routes) and then all the
>>> route and other schedule information is available from some other DB
>>>
>>> B) A point where all the world's public transport access points (bus
>>> stops,station etc) and all the routes are in OSM and all the other
>>> schedule information is available from some other DB
>>>
>>> C) A point where all the world's transport schedules are in OSM and
>>> get updated on a regular basis by Bots?
>





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