geodistance.sql

-- Haversine Formula based geodistance, calibrated for use in danish latitudes (6371 used as radius)
CREATE OR REPLACE FUNCTION service.geodistance(a point, b point)
  RETURNS double precision AS
$BODY$
SELECT acos(
  sin(radians($1[0]))*sin(radians($2[0])) +
  cos(radians($1[0]))*cos(radians($2[0]))*cos(radians($2[1])-radians($1[1]))
)*6371 AS distance;
$BODY$
  LANGUAGE sql IMMUTABLE
  COST 100;