User:Rftwiki/geofence
A geofence is a virtual fence created by recording electronically an arbitrarily complex polygonal subset, area, or region of geography usually from a map of that geography. The term is usually associated with GPS mapping of vehicles or other assets in motion, wherein location data can accurately and instantaneously be determined using a global positioning receiver on or with the asset. The “fence” is established when some such electronically tracked asset enters or leaves this predefined area thereby triggering a secondary event or alert like an email or SMS text message. GeofenceTM is a trademark of RFTrax which specializes in GPS based asset tracking.