[Tagging] Lane dividers

Martin Vonwald imagic.osm at gmail.com
Thu Oct 18 07:26:23 GMT 2012


2012/10/17 Tobias Knerr <osm at tobias-knerr.de>:
> You can distinguish at most 4 types of dividers with two pairs of yes/no
> - but there are a lot more types out there. That's a big part of the
> original divider proposal, which even includes values like "dots".
> For example, how do you reconstruct the distinction between one or two
> solid lines from a "crossing:lanes=...no|no..."? Besides the different
> visual appearance, there are also subtly different legal meanings here.

I also thought about more values but I'm not sure if they would help
or unnecessarily complicate things. I'm asking myself if we really
need to tag how the divider looks like or if it is enough to tag the
effect (like for one-ways).


> Another possible idea (= not the same as a finished solution) would be
> to introduce something like this:
>
> type:divider = solid_line|double_solid_line|dashed_line|kerb
>
> Basically, use the idea of lanes, but a different suffix - and
> consequently a different number of values. This has the advantage to
> allow multiple tags for a divider (e.g. colour:divider to distinguish
> white and yellow markings).

Hm... not too bad. But introduces another suffix that has to be
supported. On the other hand that's not really an argument against,
because any applications has to support a new divider key no matter
how we solve it. So again: not too bad.

Two issues I see here:
* type:divider - this key doesn't seem very intuitive to me. No, I
don't have a better one right now but I'll start thinking ;-)
* values: if we tag the way the divider looks, any application has to
understand all values in all countries. I'll ask again: do we really
gain important information to justify this? Of course I know the
counter-argument to my own argument: if we only tag the effect a
renderer which really renders lanes has to know how to render each
effect in each country. So no matter how we solve this, one kind of
application has a problem.

All together I think your idea is something worth exploring. I'll hope
we get some more comments on this.

Martin



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