[Tagging] Superroutes - good, bad or ugly?

Paul Allen pla16021 at gmail.com
Thu Mar 14 14:29:24 UTC 2019


On Thu, 14 Mar 2019 at 03:44, Warin <61sundowner at gmail.com> wrote:

> On 14/03/19 01:02, Paul Allen wrote:
>
>
>
> 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).
>
> IN PTV2 you list the stops in order .. so they would be listed as;
> A
> B
> D
> E
> etc
> A
> B
> C
> D
> E
> etc
>
> So it can be done in PTV2.
>

Yes, it can be done.  I said as much myself.  But it is hard to decipher.
There is nothing that
explicitly says that the bus does not  stop at C the first time the bus
passes it but does stop
the second time.  If you painfully trace out the ENTIRE route, correlating
stops and ways,
you can reach the correct conclusion.

Now consider somebody using the query tool for the bus stop at C.  Somebody
who isn't a
mapper, just a user.  Here's the route:
https://www.openstreetmap.org/relation/8592409#map=14/52.0860/-4.6644
and here's the stop: https://www.openstreetmap.org/node/5706768172 Note
that I haven't yet
included the stop on that route (although I have included it in an
incomplete variant route), but
if I had, and included it in the right order, how easy would it be for you
to figure out what is going on?
>From casual inspection, it's not easy.

However, take a look at the incomplete variant route:
https://www.openstreetmap.org/relation/8603360#map=14/52.0869/-4.6691
and imagine that were part of a superroute.  You could see, by inspecting
the subroutes in turn
(for example, on umap) that this stop is used on one route segment but not
another, even though
both segments pass along that way.

A segment end does not indicate a stop .. in PTV2. The segments need to be
> in sequential order and so do the stops.
>

A segment END?  Who's talking about segment ends?  I'm talking about a
segment which may
have more than one stop or no stops at all.  Who's talking about disordered
segments?  The whole
idea is to have the segments in order.  Who's talking about disordered
stops?  The whole idea is
to have ordered stops.

What I'm talking about is a segment of a route with its stops.  It may
share one or more ways
with a different segments of that route, and it may share one or more stops
(or none at all).  One
of us is missing what the other is saying, right now I don't know which one
of us that is.

-- 
Paul
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