[Talk-transit] Proposed Feature - RFC - Public Transport

Michał Borsuk michal.borsuk at gmail.com
Fri Dec 10 06:29:40 GMT 2010


On 9 December 2010 23:40, Michael von Glasow <michael at vonglasow.com> wrote:

>  On 12/09/2010 01:31 PM, Michał Borsuk wrote:
>
>
>
>
> There is the issue of "multiple relations per line" in oxomoa, which in my
> opinion is a total misfit. There are "roles" in relations, and different
> variants of a route can be put there.
>
> My previous post to this list contains an example of what you may encounter
> in real life. The case of a telescope line may be representable in a single
> relation, but I really do not know how to express in a single relation that
> some courses skip part of the route (the market example) and follow another
> (including some different stops)
>

IMHO You don't. OSM shows where the line passes regularly, and not how it
goes in detail. The point of bus lines on OSM is not to replace timetables
and programs like Hafas, but to show people where they can take a bus, which
passes regularly (whatever that means). For this purpose I personally do not
map for example schoolbus lines (even though legally they are open to all
passengers).

For me personally it is important to see if there is a bus line in the area,
and how's the bus stop called. Then I connect to hafas by my telephone and
find the timetable. It works in practice.


> If you have a decent way of expressing that in a single relation, please do
> share it here - I'd happily adopt that if only someone suggests a
> satisfactory solution to the issue.
>

In case of a telescope line there is no problem - simply ignore the fact
that some runs (Kurse? in German) end earlier. In case of a line which
alternates between two different paths, my idea is to add "a" and "b" to the
roles (or "forward_a" and "forward_b", but again, this is not so crucial,
because for the user the info is clear: there's a bus line. The user doesn't
care that the same bus line goes another path, s/he sees this line. If the
bus passes some place less often than every 2 hours, then I don't put the
line on OSM at all, because what's the use?


> Two, or more, relations per line is not only "illegal" (clearly against the
> principle, as it was stated by its creators), but also hell to administer,
> and JOSM-limited.
>
> Are you referring to the master relation which contains the relations for
> the route variants? In fact I don't use them in Milan
>

Yes.


> (in Munich it seems common practice and I follow that), and as of today
> renderers seem to be fine even without it. Take the following example:
>
> http://78.46.81.38/api/sketch-line?network=SITAM&ref=69&style=padua
>
> This line is made up of four relations (two variants with one relation for
> each direction),
>

That's not much different from what I deal with, and as of today I ignored
different variants out of the lack of a sensible solution (oxomoa not being
one), and the world has not collapsed. The lines I mapped appear on
öpnvkarte.de <http://xn--pnvkarte-m4a.de>, the only problem being
http://78.46.81.38/<http://78.46.81.38/api/sketch-line?network=SITAM&ref=69&style=padua>service
doesn't work. But again, I am almost alone in the area, and I have
more important issues to address, such as adding bus stops to relations.


> and OSM Server Side Script manages to put them together based on their ref
> and network tags.
>

And this is the way to go: leave the mess to be cleaned by scripts, not
humans. The author of önpvkarte managed to get all the data and make sense
of it. It should be middleware, not humans, which would deal with details
such as telescope or spoon lines (with a loop instead of a terminus).


>
> Editor support, as Dominik writes, I would not overestimate. JOSM may be
> complex, but maintaining public transportation routes is complex on itself
>

This is not a reason to limit it to one editor.


>  Potlatch and Merkaartor account for 2/3 edits together.
>
> Now this does surprise me - I would have expected a higher "market share"
> for JOSM.
>

Really? Let's see:
* ugly interface
* more difficult that the others
* written in Java, which requires >100MB installation

None of the above bother me, but I can see why some people won't try it.
Remember, mappers are not always geeks. We are.


> If you have the figures at hand, it would be interesting to find out how
> many of the people who edit public transportation data use JOSM vs. other
> editors.
>

I can tell you what I do in JOSM: adding lines to a mother relation. All
other things are done in  Potlatch. I don't even know how to import gpx to
JOSM.


> Then again - if other editors do not support all that's possible, we should
> also consider adapting the editors to support the tagging scheme we have in
> mind rather than adapting the tagging scheme to what is supported by all
> editors.
>

What is important for me is that Potlatch does well with mapping bus lines.
It doesn't even need any extensions for it.


-- 
Best regards, mit freundlichen Grüssen, meilleurs sentiments, Pozdrowienia,

Michał Borsuk
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk-transit/attachments/20101210/eddc11fd/attachment.html>


More information about the Talk-transit mailing list