> ## Documentation Index
> Fetch the complete documentation index at: https://docs.wherobots.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ST_SimplifyVW

This function simplifies the input geometry by applying the Visvalingam-Whyatt algorithm.

<img src="https://mintcdn.com/wherobots/wLm_IRUSNlHZTHJP/images/sql-functions/ST_SimplifyVW/ST_SimplifyVW.svg?fit=max&auto=format&n=wLm_IRUSNlHZTHJP&q=85&s=81983e24bd029d0ace56bdf783798751" alt="ST_SimplifyVW" width="500" height="300" data-path="images/sql-functions/ST_SimplifyVW/ST_SimplifyVW.svg" />

<Note>
  The simplification may not preserve topology, potentially producing invalid geometries. Use [ST\_SimplifyPreserveTopology](/reference/wherobots-db/geometry-data/processing/ST_SimplifyPreserveTopology) to retain valid topology after simplification.
</Note>

## Signatures

```sql theme={"system"}
ST_SimplifyVW(geom: Geometry, tolerance: Double)
```

## Parameters

<ParamField body="geom" type="Geometry" required>
  The input geometry.
</ParamField>

<ParamField body="tolerance" type="Double" required>
  The distance tolerance.
</ParamField>

## Return type

<ResponseField type="Geometry">
  The resulting geometry.
</ResponseField>

## Example

```sql theme={"system"}
SELECT ST_SimplifyVW(ST_GeomFromWKT('POLYGON((8 25, 28 22, 28 20, 15 11, 33 3, 56 30, 46 33,46 34, 47 44, 35 36, 45 33, 43 19, 29 21, 29 22,35 26, 24 39, 8 25))'), 80)
```

```
POLYGON ((8 25, 28 22, 15 11, 33 3, 56 30, 47 44, 43 19, 24 39, 8 25))
```