[Tagging] Highway property proposal "covered=yes"

Randy rwtnospam-newsgp at yahoo.com
Fri Oct 30 23:17:23 GMT 2009

Martin Koppenhoefer wrote:

>2009/10/30 Pieren <pieren3 at gmail.com>
>>On Thu, Oct 29, 2009 at 11:02 PM, Randy 
>><rwtnospam-newsgp at yahoo.com>
>>>Possibly just "building=roof"
>>>would work (not my idea, someone else suggested it).
>>I have a much bigger preference to "building=roof" or "building=cover"
>>on the element on the top instead of some attribute on some
>>hypothetical element below .
>>Adding the attribute "covered=yes" is not always possible, e.g. a
>>large balcony covering only partially a river or a simple roof in
>>farms (a open air shelter for animals or warehouse).
>>If it is to help the renderers only, then it sounds as a synonym of
>+1, I agree that it would be better to map the covering object in an
>appropriate way, and not to indirectly map it through attributes on the
>covered object, e.g. in cases that a building covers a street beeing itself
>a bridge (those cases currently are not displayed correctly in mapnik due 
>a "bug by design", that is even with the building beeing on level 1 and
>tagged as bridge=yes the street is displayed like it was on top of it).
>On the other hand for galleries (covering structures like in alpine areas 
>protect the street, but unlike a tunnel open to one or both sides) and
>arcades (and colonades) I would prefer to have the attribute on the road.
>Tunnel should be used for real tunnels and not for all kind of structures
>where a street is covered.
>Then there is a third kind of way: those that are completely inside
>buildings (shopping malls, generally corridors and hallways, all kind of
>indoor-ways). I'd like to see a Key indoor for those to stop the abusement
>of the tunnel-key.

a) I didn't suggest using "covered=yes" for areas, for the reason Pieren 
gave, i.e. partial coverage. However, there are limited situations when I 
think tagging areas as covered may be appropriate, so I wouldn't want to 
restrict it.

b) Yes, I agree that when one can clearly differentiate levels for the 
components involved the current layering method should be used. I also 
agree that abusing the use of tunnel is inappropriate. When there is 
"unmappable" access to a tunnel, such as an open side, then it is not a 

c) However, as Martin agreed, there are cases where it is a 
misrepresentation, at the least, to map a way and a building in different 
layers. Take for an example a four story department floor where the first 
floor is undercut to allow an exterior sheltered pedestrian way.

d) Is it better to proliferate tags, i.e., have separate tags for interior 
ways and exterior covered ways, or to have a single tag that applies to 
both? I can see arguments both ways, but tend to lean toward simplification.


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