edge_distance_to_edge()

double edge_distance_to_edge	(	const GEOGRAPHIC_EDGE *	e1,
		const GEOGRAPHIC_EDGE *	e2,
		GEOGRAPHIC_POINT *	closest1,
		GEOGRAPHIC_POINT *	closest2
	)

Calculate the distance between two edges.

IMPORTANT: this test does not check for edge intersection!!! (distance == 0) You have to check for intersection before calling this function.

Definition at line 1271 of file lwgeodetic.c.

{
        double d;
        GEOGRAPHIC_POINT gcp1s, gcp1e, gcp2s, gcp2e, c1, c2;
        double d1s = edge_distance_to_point(e1, &(e2->start), &gcp1s);
        double d1e = edge_distance_to_point(e1, &(e2->end), &gcp1e);
        double d2s = edge_distance_to_point(e2, &(e1->start), &gcp2s);
        double d2e = edge_distance_to_point(e2, &(e1->end), &gcp2e);
 
        d = d1s;
        c1 = gcp1s;
        c2 = e2->start;
 
        if ( d1e < d )
        {
                d = d1e;
                c1 = gcp1e;
                c2 = e2->end;
        }
 
        if ( d2s < d )
        {
                d = d2s;
                c1 = e1->start;
                c2 = gcp2s;
        }
 
        if ( d2e < d )
        {
                d = d2e;
                c1 = e1->end;
                c2 = gcp2e;
        }
 
        if ( closest1 ) *closest1 = c1;
        if ( closest2 ) *closest2 = c2;
 
        return d;
}

References edge_distance_to_point(), GEOGRAPHIC_EDGE::end, and GEOGRAPHIC_EDGE::start.

Referenced by circ_tree_distance_tree_internal(), ptarray_distance_spheroid(), and test_edge_distance_to_edge().

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