[Tagging] how to map simple buildings

["Christian Müller"]

Also note that there are some implications in 2d mapnik rendering.

With the building outline we define and the mapnik rules that were
set upto render everything highway=* _above_ anything else, the
renderer _will_ overlap a building outline with a pedestrian area.

Esp. when (highway=pedestrian area=yes) connects seamless to the
ground level building part:

 __ building outline extents up to here
/
|
v
._____________flat_roof_
| level 3
|_______________________
| level 2
|___________________________
             | ground level
pedestrian   |
area outside |______________

             ^~ pedestrian area extents up to here


Greetings