What outline should the building have in this case? Should I also include this protruding part of the building and mark the path underneath with “covered=yes”, or should I not take this hanging part into account?
I define outline as the part on the ground, so I wouldn’t take this hanging part into account at first step.
Only if you want to create 3D mappings it has to be relevant for you.
There’s no clear definition, unfortunately.
In this case, I understand omitting the protruding part from the building outline. It would definitely make mapping entrances and such easier.
But I would hesitate to turn that into a general rule. With buildings where significant parts of the buildings are above-ground (e.g. supported by pillars), the ground-level footprint gives a misleading impression of the building’s shape and size.