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\$1Centroid
<a name="ST_Centroid-function"></a>

ST\$1Centroid returns a point that represents a centroid of a geometry as follows:
+ For `POINT` geometries, it returns the point whose coordinates are the average of the coordinates of the points in the geometry. 
+ For `LINESTRING` geometries, it returns the point whose coordinates are the weighted average of the midpoints of the segments of the geometry, where the weights are the lengths of the segments of the geometry.
+ For `POLYGON` geometries, it returns the point whose coordinates are the weighted average of the centroids of a triangulation of the areal geometry where the weights are the areas of the triangles in the triangulation.
+ For geometry collections, it returns the weighted average of the centroids of the geometries of maximum topological dimension in the geometry collection.

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

```
ST_Centroid(geom)
```

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

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

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

`GEOMETRY` 

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

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

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

The following SQL returns central point of an input linestring. 

```
SELECT ST_AsEWKT(ST_Centroid(ST_GeomFromText('LINESTRING(110 40, 2 3, -10 80, -7 9, -22 -33)', 4326)))
```

```
                     st_asewkt
----------------------------------------------------
 SRID=4326;POINT(15.6965103455214 27.0206782881905)
```