[Tagging] Highway property proposal "covered=yes"

Randy rwtnospam-newsgp at yahoo.com
Wed Oct 28 21:04:13 GMT 2009

I have run into several situations where a service road extends under a 
covered area, such as a building.

Layering is one way to tag the building/road system, but, technically, it 
is not always a correct way. Example: a building on the ground is at layer 
0, associated with any pedestrian ways leading to it. That building has a 
small ground level footprint, a small shop, a stairway, and an elevator. 
The second floor (first floor to many) extends over a much larger area, 
and a service road/parking area is under that floor, open on three sides, 
therefore not a tunnel. The service road should also be at the same layer 
as the ground floor and the pedestrian ways. The second floor is 
contiguous, so separating the building into two pieces one at layer 0 and 
one at layer 1 is also misleading. Unless the building is mapped as a 
complex relation of stacked layers, there is no appropriate way, that I'm 
aware of, to map this situation. And, from aerial photography, it's guess 
work to map the hidden layers, anyway. GPS surveys can also be questionable.

I propose that an additional property for highway of "covered=yes" be used 
for this and similar situations, where a road extends under a building, 
roof attached to a building, etc.

In addition to providing a proper tagging method, there is an added 
benefit. There has been a continuing series of rendering bug reports about 
roads being on top of buildings rather than under them, independent of 
layering. This property tag would also make it much easier for renderers 
to render the way differently than on top of the building (or other 
structure), independent of rendering sequence. My proposed rendering would 
be parallel dashed lines with transparent fill, similar to a tunnel, 
without the entries/exits being drawn.


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