What are Data layers?

You can select a range of data and information layers such as observations, power outages, river heights, VicRoads road closures and marine bathymetry.

You can select as many or as few of these layers as you choose.  However, be warned if you turn too many on at once you could end up with a messy view.

See How to manage your information layers if your Map View looks like the one above.