A Geofence, by definition, means a virtual geographic boundary, defined by GPS or RFID technology, that enables software to trigger a response when a mobile device enters or leaves a particular area.
As per Wikipedia,
A geofence is a virtual perimeter for a real-world geographic area. A geofence could be dynamically generated—as in a radius around a store or point location, or a geofence can be a predefined set of boundaries, like school attendance zones or neighborhood boundaries.
The use of a geofence is called geofencing, and one example of usage involves a location-aware device of a location-based service (LBS) user entering or exiting a geo-fence. This activity could trigger an alert to the device’s user as well as send a message to the geofence operator. This info, which could contain the location of the device, could be sent to a mobile phone or an email account.
AWS Vehicle Tracking allows you to create your own suitable geofences as per your requirement. For example, you may want to mark your office compound or your go-down area as a geofence. You may mark it as a circle or as a square. You may set appropriate alerts to notify you whenever your vehicle enters or exits this geofence area. You may also choose to view the report for any given day.
Geofence Shown on the map (Above).
Geofence Report (Above)