Geofencing: What It Is and How It Works

Find out what Geofencing can do for you

Geofencing is the ability to create a virtual fence or imaginary boundary on a map. It can include alerts to notify you when a device moves into or out of the boundary defined by the virtual fence.

Geofencing technologies and apps can do things like:

  • Notify you when your child leaves school.
  • Set areas your teen is allowed to drive in or designate areas where they are not allowed to go.
  • Combine with smart home systems to allow lights to turn on when you arrive home, locks to unlock or lock, or heating or cooling to ramp up or turn down.

Geofencing is an outgrowth of location services, a common system included with most smartphones, computers, watches, and some specialized tracking devices.

What Is Geofencing?

Geofencing is a location-based service that uses GPS (Global Positioning System), RFID (Radio Frequency Identification), Wi-Fi, cellular data or combinations of the above to determine the location of the device that is being tracked.

In most cases, the tracking device is a smartphone, computer, or watch. It can also be a device designed specifically for a pretty wide variety of situations. Some more examples can include dog collars with built-in GPS tracker, RFID tags used to track inventory in a warehouse, and navigation systems built-in to cars, trucks, or other vehicles.

The location of the device being tracked is compared against a virtual geographic boundary usually created on a map within the geofence app. When the device being tracked crosses the geofence boundary it triggers an event defined by the app. The event may be to send a notification or perform a function such as turning on or off the lights, heating or cooling in the designated geofenced zone.

Fence running along hillside
Geofencing can tell which side of the fence you are on. Witizia/Pixabay CCO

How Geofencing Works

Geofencing is used in advanced location-based services to determine when a device being tracked is within or has exited a geographic boundary. To perform this function the geofencing app needs to be able to access the real-time location data being sent by the tracked device. In most cases, the information is in the form of latitude and longitude coordinates derived from a GPS-enabled device.

The coordinate is compared against the boundary defined by the geofence and generates a trigger event for either being inside or outside the boundary.

Geofencing Examples

Geofencing has a large number of uses, some quite surprising, and some fairly mundane, but all are examples of how this technology can be used:

  • Livestock monitoring — One of the earliest uses of geofencing was in the livestock industry. A small percentage of cattle in a herd would be outfitted with GPS tracking devices. If the monitored cattle left an area defined by the geofence an alert was sent to let the rancher now the herd had moved beyond the boundary the rancher had created with the geofence.
  • Teen driver monitoring Teen driver monitoring systems allow you to set areas your teen is allowed to drive in or areas your teen is not allowed to go. Some of these systems allow for scheduling, letting your child drive to the beach on weekends, for instance, but not during school days. Most of these systems are installed on the driver's smartphone, but a few of them can also use a cars built-in navigation system or its OBDII (On-Board Diagnostic) port
  • Smart home Geofencing technology can be combined with smart home systems to allow lights to turn on when you arrive home, locks to unlock or lock, heating or cooling to ramp up or turn down. One example is HomeKit, which includes a Leaving Home and Arriving Home set of automation macros triggered by a geofence around your house. When you arrive home lights may turn on, an exterior door could unlock and the stereo may be tuned to your favorite station. When you physically leave, automatic actions can take place: the garage door could close, doors lock, lights dim, and heat or cooling levels can decrease.
  • Trucking services — Fleet managers used geofencing to create routes for drivers to use. If a truck moved outside of the route defined by the geofence an alert could be sent to the fleet manager or the driver to let them know they had strayed from the prescribed route. Used primarily as a security tool to safeguard a trucking fleet from theft or as an efficiency aid to keep the cost down by forcing the use of preferred routes.
  • Business marketing Perhaps one of the early uses was the creation of location-based mobile ads that worked on smartphones with location services. These types of apps may serve up tips or information about items going on sale when the smartphone was near a store or service. Similar apps are in use in the tourism industry, using geofencing to provide information about an exhibit or historical site that you are close to.
  • Pet location service — Similar to livestock monitoring, the pet location system used a GPS enabled collar to monitor the location of the pet. When the pet moved beyond the virtual boundary, perhaps your property lines, an alert would be sent to the owner. Some of the pet systems allowed for multiple geofences, each with a different alert that could be sent such as your dog is in the roses again, or slightly worse, your dog is in the neighbor's roses again. The pet location systems also usually offered GPS tracking to help recover your pet if it becomes lost.
  • Productivity — Geofencing is used in various apps to assist you in productivity. Geofencing can be used to let a productivity app know when you leave or enter an area. As an example, when you leave work before you get out of the parking lot you may receive a message reminding you to pick up some groceries on the way home. When you arrive home, you may be reminded that you need to take the trash out tonight.