[Tagging] Superroutes - good, bad or ugly?
Peter Elderson
pelderson at gmail.com
Wed Mar 13 15:02:06 UTC 2019
I can't answer the question for busrelations.
For long hiking routes and walking node networks, relations containing
relations are very important.
Without those, maintenance of long hiking routes becomes a p.i.t.b,
sometimes near impossible.
Rendering can be done without superroutes, just by rendering each piece
separately. But datausers need to resolve the hierarchy. Waymarkedtrails
does that nicely for long recreational routes: Just replace every member
relation with its content, recursively. Works nicely- if it's only ways in
the lowest level relations.
I'm not sure if your case needs just rendering or also data
use/routing/navigation.
Vr gr Peter Elderson
Op wo 13 mrt. 2019 om 15:05 schreef Paul Allen <pla16021 at gmail.com>:
> On Wed, 13 Mar 2019 at 13:29, Andy Townsend <ajt1047 at gmail.com> wrote:
>
>> On 13/03/2019 13:18, Paul Allen wrote:
>> > I've hesitated to ask this question for months now: what's the
>> > consensus on superroutes?
>>
>> In what context are you asking the question? I can think of examples
>> where the answer would be "a really bad idea" and others where the
>> answer would be "essential; there's really no other sensible way to have
>> that data in OSM".
>>
>
> That's more positive than I expected: they're not always on a par with
> eating babies but the use
> has to be justifiable.
>
> Can I get the data into OSM without a superroute? Sure. Is that data
> useful without a superroute?
> Not so much. It is this bus route:
> https://www.openstreetmap.org/relation/8592409#map=14/52.0860/-4.6644
> That is incomplete and has some omissions and errors. I really ought to
> fix it, but I had
> this thought about superroutes and realized if I fixed and then found out
> I could use a
> superroute I'd later have to rework a few things.
>
> It's a circular. It starts at what can loosely be called the bus
> station. It does what can loosely
> be called a hairy circular route to return to the bus station. The route
> then continues on a side
> trip and eventually returns to the bus station, completing the "circle."
>
> There are places where the bus goes into a dead-end and gets out by
> reversing into a side
> junction. This differs from similar manoeuvres at a terminus of a
> non-circular route because
> passengers are on board. It does a loop-the-loop. It appears to do a
> figure-8 but actually
> there are other side-trips that mean it really isn't.
>
> One problem that I don't see a solution for in PTV1, PTV2 or "we don't tag
> it PTV3" is a stop
> that is ignored on the first pass but comes into play on the second pass.
> The bus starts at
> the bus station A, passes through nodes B, C and D and turns right at D to
> E. On this pass
> through C it ignores the bus stop there. After it's gone through the
> alphabet back to A, it
> again goes through B, C and D but this time turns left to alpha, beta,
> etc. On this pass it
> does stop at C. Piling all the stops into the relation may lead the
> routers to conclude that
> you can wait at the stop C to get directly to E when you can't (but you
> can get on at C to take
> a detour through the greek alphabet and eventually get to E because it's a
> circular).
>
> Splitting it into route segments would fix the problem with the stop at
> C. On one segment it isn't
> a listed stop. On another segment it is.
>
> Splitting it into route segments would also make it clearer what happens
> in the loop-the-loop
> and the figure-of-8 in the town centre, if the splits are chosen
> judiciously. If I'm really clever
> I can find splits that make the variant routes fit in nicely, too. You
> think that route is insane?
> Wait until I add the variants.
>
> Best of all, I could pull these into umap. It would then be possible to
> display route segments
> in turn to see where the bus goes rather than trying to puzzle it out from
> the overall route. Yes,
> if you're very familiar with OSM you can puzzle it out from the relation,
> but most people can't do
> that (and I find it difficult, even with knowledge of how the route runs).
>
> So, good idea, bad idea, or should I stick to eating babies as that would
> be more socially
> acceptable?
>
> --
> Paul
>
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