[Talk-it] mapnik ed i multipoligoni (ancora)

[Martin Koppenhoefer]

allora, sulla [dev]-list c'erano due risposte (in inglese, mi permetto
di incollare qui sperando che capite tutti):

1. Lennard (chi mantiene lo stylesheet di mapnik):
Well, what do you expect when you add an inner way (the building) to
an area object (the administrative region)? Never mind any additional
tags. It will be interpreted as such: a gap in the area. An enclave,
in this particular case, with an appropriate line drawn around the
building.

So there you have it: don't add stuff to area datatypes that doesn't
belong in them.

2. Frederik
This is what I would have expected. At least any code that I have
written will completely disregard outer/inner tags and instead find
out for itself whether something is outer or inner.

Adding anything other than rings of a polygon to a multipolygon
relation is not supported.

I know the practice of adding "admin centre" nodes or so but I don't
think it makes sense. If you really want to model this right then you
need to do:

(relation 1) is a type=whatever that represents the country

(relation 2) is a type=boundary or multipolygon that represents the
country's border or land and is member of r1 in role "border"

(node/way 3) represents the admin center and is member of r1 in role
"admin_centre"

Countries have admin centres, and countries have boundaries - not
"boundaries have admin centres", and neither "countries are
boundaries".

Bye
Frederik


ciao,
Martin