ST_3DLineInterpolatePoint
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## Name

ST_3DLineInterpolatePoint — Returns a point interpolated along a 3D line at a fractional location.

## Synopsis

`geometry ST_3DLineInterpolatePoint(`geometry a_linestring, float8 a_fraction`)`;

## Description

Returns a point interpolated along a 3D line at a fractional location. First argument must be a LINESTRING. Second argument is a float between 0 and 1 representing the point location as a fraction of line length. The M value is interpolated if present.

ST_LineInterpolatePoint computes points in 2D and then interpolates the values for Z and M, while this function computes points in 3D and only interpolates the M value.

Availability: 3.0.0

This function supports 3d and will not drop the z-index.

## Examples

Return point 20% along 3D line

    SELECT ST_AsText(
        ST_3DLineInterpolatePoint('LINESTRING(25 50 70, 100 125 90, 150 190 200)',
            0.20));

       st_asetext
    ----------------
     POINT Z (59.0675892910822 84.0675892910822 79.0846904776219)

## See Also

ST_LineInterpolatePoint, ST_LineInterpolatePoints, ST_LineLocatePoint

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