How to add policy action permission for Location service CalculateRouteMatrix?

Using Postman to send a request to "/routes/v0/calculators/{{ROUTE_CALCULATOR}}/calculate/route-matrix" fails with the message:

User: {{USER}} is not authorized to perform: geo:CalculateRouteMatrix on resource: arn:aws:geo:{{RESOURCE}}

In the IAM Policy Editor, there is not an option for CalculateRouteMatrix; only CalculateRoute.

Calling the /calculate/route API does work correctly, so it does not appear to be a problem in my URL or signing process.

Am I doing something wrong or is this a bug?

Thanks