[Tagging] Tagging problem for a river running in a culvert below a track / wiki votes enforcement

[Mateusz Konieczny]

On Wed, 27 Jan 2016 09:53:14 +1100
Warin <61sundowner at gmail.com> wrote:

> On 27/01/2016 8:50 AM, Clifford Snow wrote:
> >
> > On Tue, Jan 26, 2016 at 1:14 PM, Warin <61sundowner at gmail.com 
> > <mailto:61sundowner at gmail.com>> wrote:
> >
> >     layer=-1 to me says this is below natural ground level. And here
> >     that is not the case - the road is above natural ground level
> > and that should be tagged layer=1 .. to be absolutely technically
> > correct.
> >
> >      But many use the layer=-1 on culverts as a convenience of less
> > work.
> >
> >             tunnel=building_passage
> >
> >         I am not understanding where that tag would be applied. What
> >         would be
> >         tagged this way?
> >
> >
> >     The convention it to tag what is inside the tunnel. Similar to a
> >     bridge where what is on the bridge carries the tag.
> >
> >
> > According to the wiki:
> >
> >     Layer provides absolutely no information about relative or
> >     absolute height difference of objects which do not immediately
> >     cross or overlap. A change in layer should not be used to
> > indicate a change in elevation. A bridge is at layer 1 even if it
> > is only several feet above sea level while the peak of Mount
> > Everest is at layer 0 even though it is 8848 meters above sea level.
> >
> >     Negative values do not imply that object is underground, use
> >     location
> >     <https://wiki.openstreetmap.org/wiki/Key:location>=underground
> >     <https://wiki.openstreetmap.org/w/index.php?title=Tag:location%3Dunderground&action=edit&redlink=1>
> > for this purpose.
> >
> > Since it is a culvert, going under a road, I use layer=-1. If you
> > tag it layer=1, then you are saying the stream is above the road.
> 
> Err no.
> I would prefer to tag the road at layer=1 as that is elevated
> compared to what naturally existed before. Note this is a
> 'preference'. I too take the path of less work compared to being
> absolutely technically correct.
> 
> > Which might be correct in some instances, but looking at the
> > picture, it looks like it goes under the road. If you call the slab
> > of concrete a bridge, then layer=1 would be correct.
> >
> > Clifford
> >
> 
> 
> I think the wiki is deceptive in claim level=0 does not imply
> anything. I think it implies the"local ground level"

level=0 means that given object is at ground floor of building. ( see
https://wiki.openstreetmap.org/wiki/Key:level ).

layer=0 (or better and more common - lack of layer tag) means that it
is above intersecting objects tagged with layer=-1, layer=-2 etc and
below intersecting objects tagged with layer=1, layer=2 etc.

location=underground, location=overground etc give information about
position relative to the ground.