Here are a few images that show how easy it is to add a new object (in this case a city) to the map and to edit its shape.  Other map objects that may be added include several different kinds of roads and freshwater objects.

This image shows what it looks like when you are editing the shape of the new map object.

This image shows the final result of adding a new city to the map and editing its shape.  The entire process took only a couple of minutes.

Here is an example of a few cities that have been added to a local area map.