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# RS_ConvexHull

Return the convex hull geometry of the raster including the NoDataBandValue band pixels.
For regular shaped and non-skewed rasters, this gives more or less the same result as RS\_Envelope and hence is only useful for irregularly shaped or skewed rasters.

<img src="https://mintcdn.com/wherobots/AayJA2u8CknIeTgt/images/sql-functions/RS_ConvexHull/RS_ConvexHull.svg?fit=max&auto=format&n=AayJA2u8CknIeTgt&q=85&s=f854f810d027edb37c7208b5619249f9" alt="RS_ConvexHull" width="700" height="390" data-path="images/sql-functions/RS_ConvexHull/RS_ConvexHull.svg" />

## Signatures

```sql theme={"system"}
RS_ConvexHull(raster: Raster)
```

## Parameters

<ParamField body="raster" type="Raster" required>
  The input raster.
</ParamField>

## Return type

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

## Example

```sql theme={"system"}
SELECT RS_ConvexHull(RS_MakeEmptyRaster(1, 5, 10, 156, -132, 5, 10, 3, 5, 0));
```

```
POLYGON ((156 -132, 181 -107, 211 -7, 186 -32, 156 -132))
```