2017-12-11 1:25 GMT+01:00 Nick Bolten <nbol...@gmail.com>:
> > Unfortunately, this breaks the semantic relationship between sidewalks
> and the rest of the road ("this section of sidewalk belongs to that road
> section"). Many applications do need that relationship, and it's pretty
> much impossible to derive it automatically from separately mapped sidewalk
> ways.
>
> Absolutely, this is an open problem. However, there's no reason we can't
> tag streets with `sidewalk=left/right/yes/no` to keep that question
> answerable, while putting the pedestrian network itself (and its details)
> on proper ways.
>
we could use the type=area relation (or something similar) to virtually
join sidewalks and roads, opening also the possibility to define / connect
barriers like kerbs, guard rails, fences and interruptions like entrances,
lowered kerbs, etc. implicitly.
In addition, the question, 'does this street have a sidewalk?' is
> answerable for separate ways using geometric relationships, even if a
> `sidewalk=* tag` were missing.
>
this is guesswork, you can't be sure just because of proximity, you can
only hope (there could be a step in the terrain, one way running much
higher than the other, "disconnecting" the sidewalk from the road, or
barriers like walls and guard rails (as you can't expect everything to be
mapped, and even if it were, it would be complicated / expensive to
understand all situations for every sidewalk in the planet).
Cheers,
Martin
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