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List:       geos-devel
Subject:    Re: [geos-devel] Holes in holes
From:       strk <strk () keybit ! net>
Date:       2009-11-27 17:31:42
Message-ID: 20091127173141.GJ12065 () keybit ! net
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On Fri, Nov 27, 2009 at 02:47:17AM +0100, Frederik Ramm wrote:

> I have another remotely related question, that concerns the direction of 
> a polygon ring (CW or CCW). When I create a polygon with the 
> createPolygon factory method and pass it a number of rings, do I have to 
> take care that they spin in the right direction, or will GEOS make sure 
> that a correct polygon is created?

The createPolygon method takes an explicit shell and a list of holes.
You don't need to care about direction.

GEOS won't check validity automatic.
Use Geometry::isValid() if you want to check that.
Any ring direction is OGC valid.

--strk;

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