Geofencing is a technology for setting virtual boundaries and triggering events when these boundaries are crossed by a mobile device on which certain software is installed. Various geolocation technologies, such as GPS or triangulation of a signal from Wi-Fi access points or cell towers, determine whether the device has crossed the boundary.
What geofencing is used for
Geofencing has many applications, some legitimate, others not.
- Advertising. A retail chain can send special offers to customers when they are near one of its brick and mortar stores.
- Harvesting user information. Store owners can see how often customers visit, how much time they spend inside, and so on.
- Reminders. When the user approaches a certain location (for example, a store), a task tracker app can send a reminder of a task that should be performed at this location.
- Smart home control. When the user approaches home, an app can command the controller to turn on the kettle, power up some lights, or open the garage door.
- Logistics. An can notify a warehouse operator when vehicles arrive for loading or unloading.
- Spying. Stalkerware apps can secretly track the device owner using geofencing to notify the stalker about the victim’s movements.
- Parental control. An app can notify parents if their child leaves a safe zone, such as a yard or school.
How geofencing works
Geofencing comprises two principal tasks.
- Zone management. The defining of zones and setting of events to be triggered when a device crosses zone boundaries.
- Event initiation. The triggering of an action by means of leaving or entering a zone. The action, or “event,” can be triggered on the device itself (for example, displaying an ad on a smartphone) or on some other device (for example, switching on a smart kettle). GPS, cellular networks, Wi-Fi, Bluetooth beacons, and other technologies and methods can determine the device’s location. Apps using geofencing typically require access to location data.
Depending on the purpose of the app, these two types of tasks can be implemented on multiple devices (for example, advertising and parental control applications work that way) or just one (perhaps only one person needs reminders, and on only one device.
An early history of geofencing on mobile devices
For iOS, geofencing was a new feature in version 5, back in 2011. The built-in Reminders app used it to trigger reminders not at a specified time, but when the device was in a particular place.
Geofencing became available in Android two years later, in version 3.1 of Google Play services. Although the current version of Android at the time was 4.3, the new feature supported older OS versions — back to Android 2.2 (Froyo).