[Tagging] How to solve the problem with relation overload?

Martin Koppenhoefer dieterdreist at gmail.com
Fri Nov 30 11:22:10 GMT 2012


2012/11/30 Pieren <pieren3 at gmail.com>:
> On Fri, Nov 30, 2012 at 11:41 AM, Martin Koppenhoefer
> <dieterdreist at gmail.com> wrote:
>>> [only nodes for routes]
>> not a good idea IMHO, as it makes editing far more complex (you will
>> have to understand from just a collection of nodes which ways are
>> effectively part of a route relation).
>
> Not necessarily. Creating routes will be more or less the same if your
> editor highlights the ways between the nodes.


the editor will have to do routing (for psv) and therefor will be
depending besides the nodes also on correct psv-access-tagging.
Imagine a railway route over a long distance, how would you even
download the relation if you had only some occassional nodes?
Dependent on the following edits the routes might still become
ambigous (alternatives and it is not clear which road exactly the bus
takes).


> But their are three
> advantages : intersection nodes are quite stable in OSM, more than
> single nodes or ways.


probably true, yes, but IF someone deletes the intersection (or
unglues and the original intersection node gets moved to a position
where it is not on the route any more) instead of a small and simple
to fill hole in the route you might come to a situation where it is
not clear any more which way the bus takes, or where it simply becomes
valid but wrong (and much harder to detect).


> And last but not least, routes will not have to split ways just
> because a bus is turning left or right at intersection.


that is a plus, I agree.

I am still very sceptical towards moving from an explicit (unambigous)
mapping style to an implicit one, that requires intensive calculations
(routing for psv) to simply get the route, and that will break in a
way that it would mostly remain valid (so it's hard to find) but
probably not correct.

cheers,
Martin



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