ST_ClosestPoint
Name
ST_ClosestPoint — Returns the 2-dimensional point on g1 that is closest to g2. This is the first point of the shortest line.
Synopsis
geometry
ST_ClosestPoint
(
geometry
g1
, geometry
g2
)
;
Description
Returns the 2-dimensional point on g1 that is closest to g2. This is the first point of the shortest line.
![[Note]](images/note.png)
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If you have a 3D Geometry, you may prefer to use ST_3DClosestPoint . |
Availability: 1.5.0
Examples
Closest between point and linestring is the point itself, but closest point between a linestring and point is the point on line string that is closest.
SELECT ST_AsText(ST_ClosestPoint(pt,line)) AS cp_pt_line, ST_AsText(ST_ClosestPoint(line,pt)) As cp_line_pt FROM (SELECT 'POINT(100 100)'::geometry As pt, 'LINESTRING (20 80, 98 190, 110 180, 50 75 )'::geometry As line ) As foo; cp_pt_line | cp_line_pt ----------------+------------------------------------------ POINT(100 100) | POINT(73.0769230769231 115.384615384615)
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closest point on polygon A to polygon B
SELECT ST_AsText(
ST_ClosestPoint(
ST_GeomFromText('POLYGON((175 150, 20 40, 50 60, 125 100, 175 150))'),
ST_Buffer(ST_GeomFromText('POINT(110 170)'), 20)
)
) As ptwkt;
ptwkt
------------------------------------------
POINT(140.752120669087 125.695053378061)
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