geography_tree_closestpoint()

LWGEOM* geography_tree_closestpoint	(	const LWGEOM *	lwgeom1,
		const LWGEOM *	lwgeom2,
		double	threshold
	)

Definition at line 1036 of file lwgeodetic_tree.c.

{
        CIRC_NODE* circ_tree1 = NULL;
        CIRC_NODE* circ_tree2 = NULL;
        double min_dist = FLT_MAX;
        double max_dist = FLT_MAX;
        GEOGRAPHIC_POINT closest1, closest2;
        LWGEOM *result;
        POINT4D p;
 
        circ_tree1 = lwgeom_calculate_circ_tree(lwgeom1);
        circ_tree2 = lwgeom_calculate_circ_tree(lwgeom2);
 
        /* Quietly decrease the threshold just a little to avoid cases where */
        /* the actual spheroid distance is larger than the sphere distance */
        /* causing the return value to be larger than the threshold value */
        // double threshold_radians = 0.95 * threshold / spheroid->radius;
        double threshold_radians = threshold / WGS84_RADIUS;
 
        circ_tree_distance_tree_internal(
                circ_tree1, circ_tree2, threshold_radians,
                &min_dist, &max_dist, &closest1, &closest2);
 
        p.x = rad2deg(closest1.lon);
        p.y = rad2deg(closest1.lat);
        result = (LWGEOM *)lwpoint_make2d(lwgeom_get_srid(lwgeom1), p.x, p.y);
 
        circ_tree_free(circ_tree1);
        circ_tree_free(circ_tree2);
        return result;
}

References circ_tree_distance_tree_internal(), circ_tree_free(), GEOGRAPHIC_POINT::lat, GEOGRAPHIC_POINT::lon, lwgeom_calculate_circ_tree(), lwgeom_get_srid(), lwpoint_make2d(), rad2deg, result, WGS84_RADIUS, POINT4D::x, and POINT4D::y.

Referenced by geography_closestpoint().

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