[Talk-transit] Mapping bus routes with doglegs and loops

[Jo]

Hi Paul,

I see what you mean now. I dropped the forward/backward roles on the ways a
few years ago. Recently I thought that they should be a help for the
sorting algorithm, but your example proves they aren't.

I've been developing a script, which tries to use other good relations to
fix the one it's currently run on.

For that script to be able to work, you'd need the stops in the correct
order though.

It works like this:

For a sequence of stops it tries to find other relations which have the
same sequence. The other relation with the longest sequence in common
'wins'.

Then it finds the ways adjacent to the stops on each end of the sequence,
then uses the sequence of ways that connects the stops.

We can work that way, because we have received the stops and the timetables
from the operators, but it's the opposite of what you start with, when you
have to get on the
bus to create a GPX to get an idea about one the variation routes of a
line. (After that you'd use the unstable plugin to add the stops that are
already mapped).

The script works quite well, as long as you have some 'golden' routes it
can grab way sequences from.

Polyglot

2015-02-21 21:40 GMT+01:00 Paul Johnson <baloo at ursamundi.org>:

> On Sat, Feb 21, 2015 at 2:31 PM, Jo <winfixit at gmail.com> wrote:
>
>> Hi Paul,
>>
>> It helps, when you select a subset of ways and only let JOSM sort those
>> automatically.
>>
>
> True, but if you've had to edit a section of a dogleg to add another, sub
> dogleg, this breaks, too.  The ground truth is breaking the tool.
>
>
>> Can you select one of the relations, then do Ctrl-Shft-h, then copy that
>> url.
>>
>
> No problem, one such example is the 101 Suburban Acres southbound via
> Denver & 49th and Westview
> <https://www.openstreetmap.org/relation/4614100/history>.  Towards where
> it heads off MLK to Osage Casino along East 63rd North Street, it has a
> dogleg with two branching doglegs, two of those doglegs also have a loop.
>
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