You can add a viewshed layers to any 2D grid-based map, or to a 3D surface with no tilt in the orthographic projection.  

Viewshed layers cannot be created as stand-alone map types. They must be added to an existing map. If you have only XYZ data points, you would need to grid the data using the Grids | New Grid | Grid Data command, create a grid-based map, and then add a viewshed layer. You could also display the original points by adding a post layer of the data to the map.

For example, to add a viewshed to a contour map:

1. Click Home | New Map | Contour, select a grid file and click Open.
2. Select the Contour layer in the Contents window.
3. Click Map Tools | Add to Map | Layer | Viewshed.
4. Click on the map to specify the transmitter location, and the Viewshed layer is created.

You can add a viewshed to a 3D surface map, as long as it has no tilt and it is displayed in the orthographic projection. For example:

1. Click Home | New Map | 3D Surface | Surface, select a grid file and click Open.
2. Select Map in the Contents window.
3. In the Properties window, click the View page.
4. Set the Tilt (degrees) to 90.
5. Change the Perspective to Orthographic.
6. Click Map Tools | Add to Map | Layer | Viewshed.
7. Click on the map to specify the transmitter location, and the Viewshed layer is created.

Updated October 27, 2021