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\$1Simplify
<a name="ST_Simplify-function"></a>

ST\$1Simplify returns a simplified copy of the input geometry using the Ramer-Douglas-Peucker algorithm with the given tolerance. The topology of the input geometry might not be preserved. For more information about the algorithm, see [Ramer–Douglas–Peucker algorithm](https://en.wikipedia.org/wiki/Ramer–Douglas–Peucker_algorithm) in Wikipedia. 

When ST\$1Simplify calculates distances to simplify a geometry, ST\$1Simplify operates on the 2D projection of the input geometry. 

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

```
ST_Simplify(geom, tolerance)
```

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

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

 *tolerance*   
A value of data type `DOUBLE PRECISION` that represents the tolerance level of the Ramer-Douglas-Peucker algorithm. If *tolerance* is a negative number, then zero is used. 

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

`GEOMETRY`. 

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

The dimension of the returned geometry is the same as that of the input geometry. 

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

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

The following SQL simplifies the input linestring using a Euclidean distance tolerance of 1 with the Ramer-Douglas-Peucker algorithm. The units of the distance are the same as those of the coordinates of the geometry.

```
SELECT ST_AsEWKT(ST_Simplify(ST_GeomFromText('LINESTRING(0 0,1 2,1 1,2 2,2 1)'), 1));
```

```
 st_asewkt
-----------
LINESTRING(0 0,1 2,2 1)
```