[Tagging] covered definition in the wiki

[Richard Mann]

Layers don't work when there are area/way conflicts, because the norm
for rendering is to draw areas first then ways on top. So you have to
have a flag that says "this way isn't really on top". We have a
perfectly adequate flag for this function (tunnel=yes), but people
objected to using that for things that are not strictly tunnels. So we
spawned "covered" as an alternative. I suspect it's also used to flag
whether a walkway is covered or not, which is a rather different
situation.

I just use tunnel=yes (I guess one could add something like
tunnel:type=building|cloister|avalanche|arcade, though I don't expect
anyone to use it).

In the UK
covered=yes 345
covered=no 480
tunnel=yes 7662

Richard


On Mon, Jul 19, 2010 at 9:56 PM, M∡rtin Koppenhoefer
<dieterdreist at gmail.com> wrote:
> the covered page lists these use-cases:
> A. denote that a highway, railway, pedestrian way or waterway passes
> under a building or other structure, where it is inappropriate to use
> layering as the differentiator between covered and uncovered. or where
> "covered" will more clearly define the condition.
>
>
> -> fine, but why not for those ways passing inside a building?
>
>
> B. denote that a power line, water main, water drain, etc., in a
> narrow trench, has a removable and replaceable covering, allowing for
> maintenance, and thus potentially allowing it to be traversed without
> a bridge.
>
>
> -> quite limiting. The "potentially" part is IMHO not good in a
> definition. Why must the covering be "removable and replaceable" and
> which covering is not "removable" if you put enough effort into it's
> removal? Why must the power line, water drain etc. be "in a narrow
> trench" ?
>
>
> C. denote an area such as an underground parking lot, a covered
> reservoir/cistern or even such things as an aquarium (e.g., Kelly
> Tarlton's, Auckland, NZ), when the covering is not a man-made
> structure that would allow layer differentiation.
>
> -> Why shouldn't the covering structure be man made, or does this
> exclude just man_made structures where layering cannot solve the
> problem (e.g. more than 11 levels)?
>
>
> I think we should rework this definitions. Comments?
> http://wiki.openstreetmap.org/wiki/Key:covered
>
>
> Cheers,
> Martin
>
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