lwgeom_has_orientation()

int lwgeom_has_orientation	(	const LWGEOM *	lwgeom,
		int	orientation
	)

Check clockwise orientation on LWGEOM polygons returns LW_CLOCKWISE, LW_NONE, LW_COUNTERCLOCKWISE Non-polygonal geometries return LW_NONE Geometries must have all rings correctly oriented to return a non-none orientation.

Tests that geometry is oriented LW_CLOCKWISE or LW_COUNTERCLOCKWISE.

Definition at line 93 of file lwgeom.c.

{
        switch (lwgeom->type)
        {
                case POLYGONTYPE:
                        return lwpoly_has_orientation(lwgeom_as_lwpoly(lwgeom), orientation);
 
                case TRIANGLETYPE:
                        return lwtriangle_has_orientation(lwgeom_as_lwtriangle(lwgeom), orientation);
 
                case MULTIPOLYGONTYPE:
                case COLLECTIONTYPE:
                {
                        LWCOLLECTION* coll = lwgeom_as_lwcollection(lwgeom);
                        for (uint32_t i = 0; coll && i < coll->ngeoms; i++)
                        {
                                if(!lwgeom_has_orientation(coll->geoms[i], orientation))
                                        return LW_FALSE;
                        }
                        return LW_TRUE;
                }
 
                default:
                        return LW_TRUE;
        }
        return LW_FALSE;
}

References COLLECTIONTYPE, LWCOLLECTION::geoms, LW_FALSE, LW_TRUE, lwgeom_as_lwcollection(), lwgeom_as_lwpoly(), lwgeom_as_lwtriangle(), lwgeom_has_orientation(), lwpoly_has_orientation(), lwtriangle_has_orientation(), MULTIPOLYGONTYPE, LWCOLLECTION::ngeoms, POLYGONTYPE, TRIANGLETYPE, and LWGEOM::type.

Referenced by lwgeom_has_orientation(), ST_IsPolygonCCW(), ST_IsPolygonCW(), and test_lwgeom_force_clockwise().

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