[Tagging] Questions on building-tag

[Marc Gemis]

People often say that in OSM a building refers to the typology and not
to the function. I am happy with this definition, but have some
questions on the topic.

The building page on the wiki [1] lists e.g a church, cathedral and chapel.
But what is the structural difference between a church and a cathedral
? I always thought a cathedral is where a bishop leads the messes (or
something like that).
The wiki page on cathedral tries to avoid this by saying some
buildings are build as cathedral but without a bishop, without saying
how one can see the difference between a cathedral and a church.

I understand that chapels can be attached to other buildings, but they
can also be free standing. But how different are the bigs ones then
from a small church ?

I see similar problems with rectangular buildings with one or two
entrances a couple of floors, a flat roof and a lot of windows. They
can be schools, commercial, apartments, civic buildings. I guess one
has to take the interior division into account as well to determine
the type, not ?

So can a commercial building change to a school when the interior wall
are changed? And if so, why is a church not changed into an apartment
building when the interior changes ?

Or are we just wishing that building refers to the structure and not
the function ?
Or am I overthinking the whole topic ?

Those questions came up after I tried to answer a question on a barn
used as church and community centre on the help website.

regards

m.

[1] https://wiki.openstreetmap.org/wiki/Key:building