[Talk-transit] Proposal for a new transport tag

[Andre Joost]

Am 29.02.2012 16:07, schrieb Janko Mihelić:
> Hello,
>
> The problem with rendering transit lines right now is that the busy lines
> are rendered the same as the lines that go a few times a day. Those
> differences between lines should be seen right away, but we don't have that
> information in the database right now.
>
> I agree that the best solution would be to have the whole timetable for
> different transit lines, but this is often not possible and very hard to
> maintain. Transiki<https://github.com/SteveC/transiki>  gave us some hope
> that this could be manageable, but unfortunately the project was shut down.
>
> I propose a temporary middle solution. Every bus route relation could have
> a tag similar to the
> opening_hours<http://wiki.openstreetmap.org/wiki/Key:opening_hours>tag.
> This way we could know if a line is only active on weekends, or if it
> is a night line. Or maybe it only runs in the morning and in the evening.
>
> We could upgrade this tag, and put a number of trips in each time period.
> This can be an estimate, a trip more or less a day is not much.
>
> It would look like this:
>
> Only ferquency:
> *transport_frequency*=t5
> this means that a bus route has 5 trips a day.
>
> Only days:
> *transport_frequency*=Sa-Su
> this bus route only goes on weekends
>
> Only time:
> *transport_frequency*=00:00-04:00
> Night line
>
> A little more information:
> *transport_frequency***=Mo-Fr 08:00-23:00 t30; Sa 08:00-22:00 t25
> 30 trips a day from Monday till Friday, first trip at 8 in the morning,
> last at 10 in the evening. Similar for Saturday.
>
> And so on. I added a "t" in front of the number of trips so it is easier to
> see, maybe it is not needed. Or maybe this could be done in a completely
> different way.
>

Sounds interesting. For densly populated areas, it would be better to 
give a frequency per hour, or every xy minutes.
But how should the renderer treat a service by three bus lines runnig 
every hour? Together they serve every 20 minutes, or arrive at the same 
time to give people a chance to change the bus.
The renderer has to lock up every bus service on a road, and count them 
together. This is not a simple thing with current mapnik.

Greetings,
Andre Joost