Amazon Redshift will no longer support the creation of new Python UDFs starting Patch 198. Existing Python UDFs will continue to function until June 30, 2026. For more information, 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/). 

# ST\$1Force4D
<a name="ST_Force4D-function"></a>

ST\$1Force4D returns a 4D geometry of the input geometry. For 2D geometries, the `z` and `m` coordinates of the nonempty points in the output geometry are all set to `0`. For 3DM geometries, the `z` coordinates of the nonempty points in the output geometry are all set to `0`. For 3DZ geometries, the `m` coordinates of the nonempty points in the output geometry are all set to `0`. For 4D geometries, a copy of the input geometry is returned. Empty points in the input geometry remain empty points in the output geometry.

## Syntax
<a name="ST_Force4D-function-syntax"></a>

```
ST_Force4D(geom)
```

## Arguments
<a name="ST_Force4D-function-arguments"></a>

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

## Return type
<a name="ST_Force4D-function-return"></a>

`GEOMETRY`. 

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

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

If *geom* is empty, then an empty geometry is returned. 

## Examples
<a name="ST_Force4D-function-examples"></a>

The following SQL returns a 4D geometry from a 3DM geometry. 

```
SELECT ST_AsEWKT(ST_Force4D(ST_GeomFromText('MULTIPOINT M(0 1 2, EMPTY, 2 3 4, 5 6 7)')));
```

```
st_asewkt
-----------
  MULTIPOINT ZM ((0 1 0 2),EMPTY,(2 3 0 4),(5 6 0 7))
```