Amazon Redshift will no longer support the use of Python UDFs after June 30, 2026. We will start enforcing it in phases. For more information on the details of Python end of life and migration options, see the [ blog post ](https://aws.amazon.com/blogs/big-data/amazon-redshift-python-user-defined-functions-will-reach-end-of-support-after-june-30-2026/) that was published on June 30, 2025. 

# ST\_LineInterpolatePoint
<a name="ST_LineInterpolatePoint-function"></a>

ST\_LineInterpolatePoint returns a point along a line at a fractional distance from the start of the line. 

To determine point equality, ST\_LineInterpolatePoint operates on the 2D projection of the input geometry. If the input geometry is empty, a copy of it is returned in the same dimension as the input. For 3DZ, 3DM, and 4D geometries, the `z` or `m` coordinate is the average of the `z` or `m` coordinates of the segment where the point lies.

## Syntax
<a name="ST_LineInterpolatePoint-function-syntax"></a>

```
ST_LineInterpolatePoint(geom, fraction)
```

## Arguments
<a name="ST_LineInterpolatePoint-function-arguments"></a>

 *geom*   
A value of data type `GEOMETRY` or an expression that evaluates to a `GEOMETRY` type. The subtype is `LINESTRING`. 

 *fraction*   
A value of data type `DOUBLE PRECISION` that represents the position of a point along the linestring for the line. The value is a fraction in the range 0–1, inclusive. 

## Return type
<a name="ST_LineInterpolatePoint-function-return"></a>

`GEOMETRY` of subtype `POINT`. 

If *geom* or *fraction* is null, then null is returned. 

If *geom* is empty, then the empty point is returned. 

The spatial reference system identifier (SRID) value of the returned geometry is the SRID value of the input geometry. 

If *fraction* is out of range, then an error is returned. 

If *geom* is not a linestring, then an error is returned. 

## Examples
<a name="ST_LineInterpolatePoint-function-examples"></a>

The following SQL returns a point halfway along a linestring.

```
SELECT ST_AsEWKT(ST_LineInterpolatePoint(ST_GeomFromText('LINESTRING(0 0, 5 5, 7 7, 10 10)'), 0.50));
```

```
st_asewkt
-----------
 POINT(5 5)
```

The following SQL returns a point 90 percent of the way along a linestring.

```
SELECT ST_AsEWKT(ST_LineInterpolatePoint(ST_GeomFromText('LINESTRING(0 0, 5 5, 7 7, 10 10)'), 0.90));
```

```
st_asewkt
-----------
 POINT(9 9)
```