geography_tree_shortestline()

LWGEOM* geography_tree_shortestline	(	const LWGEOM *	lwgeom1,
		const LWGEOM *	lwgeom2,
		double	threshold,
		const SPHEROID *	spheroid
	)

Definition at line 1070 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 *geoms[2];
  LWGEOM *result;
  POINT4D p1, p2;
  uint32_t srid = lwgeom1->srid;
 
  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 / spheroid->radius;
 
  circ_tree_distance_tree_internal(circ_tree1, circ_tree2, threshold_radians,
      &min_dist, &max_dist, &closest1, &closest2);
 
  p1.x = rad2deg(closest1.lon);
  p1.y = rad2deg(closest1.lat);
  p2.x = rad2deg(closest2.lon);
  p2.y = rad2deg(closest2.lat);
 
  geoms[0] = (LWGEOM *)lwpoint_make2d(srid, p1.x, p1.y);
  geoms[1] = (LWGEOM *)lwpoint_make2d(srid, p2.x, p2.y);
  result = (LWGEOM *)lwline_from_lwgeom_array(srid, 2, geoms);
 
  lwgeom_free(geoms[0]);
  lwgeom_free(geoms[1]);
  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_free(), lwline_from_lwgeom_array(), lwpoint_make2d(), rad2deg, SPHEROID::radius, result, LWGEOM::srid, POINT4D::x, and POINT4D::y.

Referenced by geography_shortestline().

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