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\$1Polygon
<a name="ST_Polygon-function"></a>

ST\$1Polygon returns a polygon geometry whose outer ring is the input linestring with the value that was input for the spatial reference system identifier (SRID). 

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

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

```
ST_Polygon(linestring, srid)
```

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

 *linestring*   
A value of data type `GEOMETRY` or an expression that evaluates to a `GEOMETRY` type. The subtype must be `LINESTRING` that represents a linestring. The *linestring* value must be closed. 

 *srid*   
A value of data type `INTEGER` that represents a SRID. 

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

`GEOMETRY` of subtype `POLYGON`.

The SRID value of the returned geometry is set to *srid*. 

If *linestring* or *srid* is null, then null is returned.

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

If *linestring* is not closed, then an error is returned.

If *srid* is negative, then an error is returned.

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

The following SQL constructs a polygon with an SRID value. 

```
SELECT ST_AsEWKT(ST_Polygon(ST_GeomFromText('LINESTRING(77.29 29.07,77.42 29.26,77.27 29.31,77.29 29.07)'),4356));
```

```
st_asewkt
-------------
 SRID=4356;POLYGON((77.29 29.07,77.42 29.26,77.27 29.31,77.29 29.07))
```