Hi,
On 02/17/11 10:23, Daniel Sabo wrote:
Can you elaborate on how having "inner" and "outer" roles helps one
in building a valid geometry?
So, this does assume that it started as a valid OSM multipolygon, if
it fails that requirement I think we're better of fixing it in OSM
than coding around it :).
A valid Simple Feature polygon needs to have a non-self-intersecting
/ non-self-touching outer ring, but inner rings are allowed to touch
outer rings. When you look at an inner line that shares an endpoint
with an outer line and ignore roles there's a 50/50 chance of
appending it to the wrong ring.
Ah, I see. I do indeed handle that with backtracking.
I do ignore the roles after the rings are built, so if there's an
outer immediately inside another outer it will just consider the 2nd
one an inner.
Makes sense. Do you do anything about touching inner rings?
Bye
Frederik
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