[geos-devel] orientation of the rings in a polygon

strk strk at keybit.net
Mon Jul 26 16:00:53 EDT 2004

On Mon, Jul 26, 2004 at 01:53:59PM -0400, Maude Giasson wrote:
> Hi all,
> In the detailed description of the Polygon, it says that "The orientation of the rings in the polygon does not matter"
> However, in my particular application, the orientation of the rings does matter.
> The polygons I'm using are the result of an intersection in GEOS.
> 1- Is it possible to get the orientation of a linearRing with GEOS ? How ?

bool CGAlgorithms::isCCW(CoordinateSequence *);
void CoordinateSequence::reverse(CoordinateSequence *);

> 2- Is it possible to set something (i.e a factory) that would guaranty a specific orientation for the rings in the polygons.

You can derive a class from Polygon and force orientation there.

> Thanks again
> Maude Giasson


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