Jacek Konieczny wrote: > > layer=-1 tells only that the thing is under layer=0 and over layer=-2, > nothing in relation to 'ground level' (some rivers or roads may have > layer=-1 or layer=1 on most of its length). > No, ground level is layer 0. A nonzero layer on a ground-level feature is an error.
However, layer=-1 does not mean it's covered by surface, if the surface has been removed. For example, during construction of a building, the basement will be open to the air. For the original question, I'd probably use layer=-1, covered=yes, underground=yes, location=underground, and enough other semi-made-up tags that one is bound to stick. In addition, it's not always clear what ground level is in dense urban environments. In part of downtown Chicago, the pre-civilization ground level is now under two levels of elevated streets. But there are buildings that fill the formerly-open spaces, so in some sense ground level has moved up two layers. Here it's probably best to explicitly label layer=0 on whatever's chosen as the current ground level. -- View this message in context: http://gis.638310.n2.nabble.com/Underground-hovering-buildings-tp6025288p6029515.html Sent from the General Discussion mailing list archive at Nabble.com. _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk