ST_ShortestLine

Signature

GEOMETRY ST_ShortestLine(GEOMETRY geomA, GEOMETRY geomB);

Description

Returns the 2-dimensional shortest LINESTRING between two geometries (geomA and geomB).

The function will only return the first shortest LINESTRING if more than one, that the function finds.

Examples

Cases with one solution

SELECT ST_ShortestLine('POINT(1 2)',
                       'LINESTRING(0 0, 4 2)') as THE_GEOM;
-- Answer: LINESTRING (1 2, 1.6 0.8)

SELECT ST_ShortestLine('POINT(1 2)',
                       'MULTILINESTRING ((0 0, 4 2), (1 4, 2 2))') as THE_GEOM;
-- Answer: LINESTRING (1 2, 1.8 2.4) 

SELECT ST_ShortestLine('POINT(4 3)',
                       'LINESTRING(0 0, 4 2)') as THE_GEOM;
-- Answer: LINESTRING (4 3, 4 2)  

SELECT ST_ShortestLine('POINT(4 3)',
                       'POLYGON ((2 4, 0 2, 3 0, 2 4))') as THE_GEOM;
-- Answer: LINESTRING (4 3, 2.353 2.5882)   

Case with two possible solutions

SELECT ST_ShortestLine('POINT(2 2)',
                       'MULTILINESTRING ((1 1, 4 1), (1 3, 4 3))') as THE_GEOM;
-- Answer: LINESTRING (2 2, 2 1)  

See also