> ## 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_HasM

Checks for the presence of M coordinate values representing measures or linear references. Returns true if the input geometry includes an M coordinate, false otherwise.

<img src="https://mintcdn.com/wherobots/fqh3gPDE0J25Lra_/images/sql-functions/ST_HasM/ST_HasM.svg?fit=max&auto=format&n=fqh3gPDE0J25Lra_&q=85&s=6ead930d9aeff30b6be6e977cdb290ec" alt="ST_HasM" width="500" height="300" data-path="images/sql-functions/ST_HasM/ST_HasM.svg" />

## Signatures

```sql theme={"system"}
ST_HasM(geom: Geometry)
```

## Parameters

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

## Return type

<ResponseField type="Boolean">
  Returns `true` or `false`.
</ResponseField>

## Example

```sql theme={"system"}
SELECT ST_HasM(
        ST_GeomFromWKT('POLYGON ZM ((30 10 5 1, 40 40 10 2, 20 40 15 3, 10 20 20 4, 30 10 5 1))')
)
```

```
True
```