This topic describes the ST_LineInterpolatePoints function. This function interpolates a point at one or more specified locations of a LineString object and returns the points.

Syntax

geometry  ST_LineInterpolatePoints(geometry  aLinestring , float8  aFraction , boolean  repeat);

Parameters

Parameter Description
aLinestring The LineString object that you want to specify.
aFraction The fraction based on which the point is interpolated into the line. The value of this parameter is a floating-point number within the range of 0 to 1.
repeat Specifies whether to allow the repeated interpolation of the point. Default value: true.

Description

  • If you set the repeat parameter to True, this function interpolates a point at every location that is represented as a fraction along the line.
  • If the result is zero or one point, this function returns the result as a point object. Otherwise, this function returns the result as a MultiPoint object.
  • This function supports 3D objects and does not delete z coordinates.
  • This function supports m coordinates.

Examples

  • Interpolate a point by using the default parameter settings.
    SELECT ST_AsText(ST_LineInterpolatePoints('LINESTRING(0 0,0 5)', 0.20));
            st_astext
---------------------------------
 MULTIPOINT(0 1,0 2,0 3,0 4,0 5)
(1 row)
  • Interpolate a point with the repeat parameter set to False.
    SELECT ST_AsText(ST_LineInterpolatePoints('LINESTRING(0 0,0 5)', 0.20, false));
 st_astext
------------
 POINT(0 1)
(1 row)