A geofence is a virtual fence or perimeter around a physical location.
Like a real fence, a geofence creates a separation between that location and
the area around it. Unlike a real fence, it can also detect movement inside
the virtual boundary.
It can be any size or shape, even a straight line between two points.
Geofences are created using mapping software, which allow the user to draw
the geofence over the desired geographic area. It is made up of a collection
of coordinates (i.e., latitude and longitude) or in the case of a circular
geofence one point that forms the center.