El Jueves, 17 de Abril de 2008, Frederik Ramm escribió: > Hi, > > > The only exceptions apparently > > being that self-intersecting polygons are allowed in OSM. > > The wiki page you cited says "In general, a 2D geometry is simple if > it contains no self-intersection." - what do they mean by "2D > geometry"? Specifically, would a self-intersecting *line* be allowed?
Oh, why, the answer is clearly in document OGC 05-126, section 6.1.6.1. I
don't know how you missed that ;-)
A Curve is a 1-dimensional geometric object that is the homeomorphic image of
a real, closed, interval D = [a,b] = {x ∈ ℜ. | a u x u b} under a mapping f:
[a,b] → ℜ 2.
A Curve is simple if it does not pass through the same Point twice (Reference
[1], section 3.12.7.3):
∀ c ∈ Curve, [a, b] = c.Domain,
c.IsSimple⇔ (∀ x1, x2 ∈ (a, b] x1 ≠ x2 ⇒ f(x1) ≠ f (x2)) ∧ (∀ x1, x2 ∈ [a,
b) x1 ≠ x2 ⇒ f(x1) ≠ f(x2))
--
----------------------------------
Iván Sánchez Ortega <[EMAIL PROTECTED]>
Someone whom you reject today, will reject you tomorrow.
signature.asc
Description: This is a digitally signed message part.
_______________________________________________ talk mailing list [email protected] http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
