The ST_DistanceToPoint() function

The ST_DistanceToPoint() function returns the distance from the start of the line to the specified point. Z coordinates and measures are ignored.

Syntax

ST_DistanceToPoint (ST_LineString, ST_Point)
ST_DistanceToPoint (ST_MultiLineString, ST_Point)

Return type

DOUBLE

Example

The following SQL statement creates the sample_geometries table with two columns. The ID column uniquely identifies each row. The geometry ST_LineString column stores sample geometries.

CREATE TABLE sample_geometries(id INTEGER, geometry ST_LINESTRING);

The following SQL statement inserts two rows into the sample_geometries table:

INSERT INTO sample_geometries(id, geometry)
VALUES
 (1,ST_LineString('LINESTRING ZM(0 0 0 0, 10 100 1000 10000)',1)),
 (2,ST_LineString('LINESTRING ZM(10 100 1000 10000, 0 0 0 0)',1));

The following SELECT statement and the corresponding result set show how to use the ST_DistanceToPoint() function to find the distance to the point at the location (1.5, 15.0):

SELECT ID, DECIMAL(ST_DistanceToPoint(geometry,ST_Point(1.5,15.0,1)),10,5)
AS DISTANCE FROM sample_geometries;

ID          DISTANCE    
----------- ------------
          1     15.07481
          2     85.42394

  2 record(s) selected.