Geofencing Part I: Don’t Mess With The Fence

What will be the next smartphone feature that will be differentiating and cool?  Seeking Alpha Blog

At the intersection of the physical and virtual world lies a mobile capability called geofencing. A context aware app that reminds you to pick up your laundry as soon as you approach the drycleaners on the way home from work? Brilliant? Scary? We asked Director of Product for Mobile, Allen Vartazarian to explain the basics of the phenomenon, address privacy concerns, the trouble with battery drain, key applications and why geofencing has finally arrived in 2013.

Q: Can you explain geofencing to the layman?

A: Geofencing is a technology that provides the ability to create a virtual fence around a geographic location in the real world. Smartphones that are location-enabled can detect when someone enters or exits these fences, which can be as large as a city block or as small as a retail store.

Q: How exactly does geofencing work?

A: In order to create a geofence, we first determine the latitude and longitude of a particular location, or set of locations. We then assign the radius of the geofences depending on the type of location. If we were to geofence a supermarket chain, for example, we might set a radius of 200 meters, but for coffee shops we would only set a radius of about 30 meters.

Once set, the location and radii of these geofences is communicated to the smartphone of those who have our mobile app installed. When and if the person then crosses into one of the fences, we record the date, time, and latitude/longitude of the event. In addition to logging this information, we can also choose to trigger a notification to the person, linking them to a survey within our app.

Q: How accurate is geofencing?


A: Geofencing is relatively (but not 100%) accurate. Though we can be very specific about defining the criteria for each geofence, there are certain technical limitations in the way that a smartphone determines your location, especially when the device is not actively being used (like when its in your purse or your pocket). Nonetheless, we are able to get a general understanding of someone’s location and can set an acceptable location accuracy threshold when attempting to understand when someone is within a geofence or not.

In a recent project, we setup geofences around a national fast food restaurant chain which triggered an alert asking if the person was dining there: over 80% of respondents said that they were at the location, with the remainder likely being at a store next door.

Stay tuned for Part II where Allen will address the applications of geofencing.