File Content: earthdistance--1.1.sql /* contrib/earthdistance/earthdistance--1.1.sql */ -- complain if script is sourced in psql, rather than via CREATE EXTENSION \echo Use "CREATE EXTENSION earthdistance" to load this file. \quit -- earth() returns the radius of the earth in meters. This is the only -- place you need to change things for the cube base distance functions -- in order to use different units (or a better value for the Earth's radius). CREATE FUNCTION earth() RETURNS float8 LANGUAGE SQL IMMUTABLE PARALLEL SAFE AS 'SELECT ''6378168''::float8'; -- Astronomers may want to change the earth function so that distances will be -- returned in degrees. To do this comment out the above definition and -- uncomment the one below. Note that doing this will break the regression -- tests. -- -- CREATE FUNCTION earth() RETURNS float8 -- LANGUAGE SQL IMMUTABLE -- AS 'SELECT 180/pi()'; -- Define domain for locations on the surface of the earth using a cube -- datatype with constraints. cube provides 3D indexing. -- The cube is restricted to be a point, no more than 3 dimensions -- (for less than 3 dimensions 0 is assumed for the missing coordinates) -- and that the point must be very near the surface of the sphere -- centered about the origin with the radius of the earth. CREATE DOMAIN earth AS cube CONSTRAINT not_point check(cube_is_point(value)) CONSTRAINT not_3d check(cube_dim(value) <= 3) CONSTRAINT on_surface check(abs(cube_distance(value, '(0)'::cube) / earth() - '1'::float8) < '10e-7'::float8); CREATE FUNCTION sec_to_gc(float8) RETURNS float8 LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE AS 'SELECT CASE WHEN $1 < 0 THEN 0::float8 WHEN $1/(2*earth()) > 1 THEN pi()*earth() ELSE 2*earth()*asin($1/(2*earth())) END'; CREATE FUNCTION gc_to_sec(float8) RETURNS float8 LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE AS 'SELECT CASE WHEN $1 < 0 THEN 0::float8 WHEN $1/earth() > pi() THEN 2*earth() ELSE 2*earth()*sin($1/(2*earth())) END'; CREATE FUNCTION ll_to_earth(float8, float8) RETURNS earth LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE AS 'SELECT cube(cube(cube(earth()*cos(radians($1))*cos(radians($2))),earth()*cos(radians($1))*sin(radians($2))),earth()*sin(radians($1)))::earth'; CREATE FUNCTION latitude(earth) RETURNS float8 LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE AS 'SELECT CASE WHEN cube_ll_coord($1, 3)/earth() < -1 THEN -90::float8 WHEN cube_ll_coord($1, 3)/earth() > 1 THEN 90::float8 ELSE degrees(asin(cube_ll_coord($1, 3)/earth())) END'; CREATE FUNCTION longitude(earth) RETURNS float8 LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE AS 'SELECT degrees(atan2(cube_ll_coord($1, 2), cube_ll_coord($1, 1)))'; CREATE FUNCTION earth_distance(earth, earth) RETURNS float8 LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE AS 'SELECT sec_to_gc(cube_distance($1, $2))'; CREATE FUNCTION earth_box(earth, float8) RETURNS cube LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE AS 'SELECT cube_enlarge($1, gc_to_sec($2), 3)'; --------------- geo_distance CREATE FUNCTION geo_distance (point, point) RETURNS float8 LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE AS 'MODULE_PATHNAME'; --------------- geo_distance as operator <@> CREATE OPERATOR <@> ( LEFTARG = point, RIGHTARG = point, PROCEDURE = geo_distance, COMMUTATOR = <@> ); Submit