ST_LineInterpolatePoint

Signature

GEOMETRY ST_LineInterpolatePoint(Geometry geom, double start)

Description

Returns a point interpolated along the input geom, starting at the given fractions. The returned geometry is a POINT.

Where:

geom is a LINESTRING or a MULTILINESTRING
start is the starting fraction (between 0 and 1). e.g start = 0.1 means that the first point will be placed at a distance equivalent to 10% of the total length of the line.

Warning

Only LINESTRING or MULTILINESTRING are supported

Examples

With `LINESTRING`

SELECT ST_LineInterpolatePoint('LINESTRING(1 1, 5 5)', 0.1);
-- Answer: POINT (1.4 1.4)

With `MULTILINESTRING`

SELECT ST_LineInterpolatePoint('MULTILINESTRING((1 1, 5 5, 1 7), 
                                         (6 1, 7 4, 6 6))', 0.5);
-- Answer: MULTIPOINT ((4.581138830084189 4.581138830084189), 
--                     (6.853553390593274 3.5606601717798214))

See also