postgresql/contrib/earthdistance/earthdistance.sql.in

91 lines
3.0 KiB
MySQL

-- Adjust this setting to control where the objects get created.
SET search_path = public;
SET autocommit TO 'on';
-- The earth functions rely on contrib/cube having been installed and loaded.
-- 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 OR REPLACE FUNCTION earth() RETURNS float8
LANGUAGE 'sql' IMMUTABLE
AS 'SELECT \'6378168\'::float8';
-- Astromers 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 OR REPLACE 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.
-- Check constraints aren't currently supported.
CREATE DOMAIN earth AS cube;
-- CONSTRAINT not_point check(is_point(earth))
-- CONSTRAINT not_3d check(cube_dim(earth) <= 3)
-- CONSTRAINT on_surface check(abs(cube_distance(earth, '(0)'::cube) /
-- earth() - 1) < '10e-12'::float8);
CREATE OR REPLACE FUNCTION sec_to_gc(float8)
RETURNS float8
LANGUAGE 'sql'
IMMUTABLE STRICT
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 OR REPLACE FUNCTION gc_to_sec(float8)
RETURNS float8
LANGUAGE 'sql'
IMMUTABLE STRICT
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 OR REPLACE FUNCTION ll_to_earth(float8, float8)
RETURNS earth
LANGUAGE 'sql'
IMMUTABLE STRICT
AS 'SELECT cube(\'(\'||earth()*cos(radians($1))*cos(radians($2))||\',\'||earth()*cos(radians($1))*sin(radians($2))||\',\'||earth()*sin(radians($1))||\')\')';
CREATE OR REPLACE FUNCTION latitude(earth)
RETURNS float8
LANGUAGE 'sql'
IMMUTABLE STRICT
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 OR REPLACE FUNCTION longitude(earth)
RETURNS float8
LANGUAGE 'sql'
IMMUTABLE STRICT
AS 'SELECT degrees(atan2(cube_ll_coord($1, 2), cube_ll_coord($1, 1)))';
CREATE OR REPLACE FUNCTION earth_distance(earth, earth)
RETURNS float8
LANGUAGE 'sql'
IMMUTABLE STRICT
AS 'SELECT sec_to_gc(cube_distance($1, $2))';
CREATE OR REPLACE FUNCTION earth_box(earth, float8)
RETURNS cube
LANGUAGE 'sql'
IMMUTABLE STRICT
AS 'SELECT cube_enlarge($1, gc_to_sec($2), 3)';
--------------- geo_distance
CREATE OR REPLACE FUNCTION geo_distance (point, point)
RETURNS float8
LANGUAGE 'C' IMMUTABLE STRICT AS 'MODULE_PATHNAME';
--------------- geo_distance as operator <@>
CREATE OPERATOR <@> (
LEFTARG = point,
RIGHTARG = point,
PROCEDURE = geo_distance,
COMMUTATOR = <@>
);