Geofence

To make the location data more useful to its customers, uLocate has developed some enhancements. For instance, users can set up "geofences" around specific locations; when a phone enters or leaves that area, an alert is triggered. This could be used to let parents know, by e-mail or SMS, when a child reaches school.

Source: wiktionary

A company like PetsMobility produces the "PetsCell," a "revolutionary waterproof A-GPS CDMA cell phone for your Pet" (as the company puts it). PetsMobility declares that / there's no hiding with the PetsCell™. […] Establish a remote programmable geofence around a yard or campus, and use handy notification features that alert your cell phone when a breach occurs.

Source: wiktionary

A geofence could be a mile or more around a store or it could be fifty feet from the front door, whatever the business decides.

Source: wiktionary

In the event that the secured lot and locking systems emplaced fail to keep a load from being stolen, by emplacing a geofence (or electronic boundary) around the stationary load, the user or a control center can be notified immediately when the load begins to move and crosses the electronic boundary, which allows for an immediate response protocol, which can enhance the chances for recovery exponentially.

Source: wiktionary