Software that can guess your location from your photos is not new. Remember Google Goggles, the Android app that recognizes famous landmarks in your photos? It’s a fun party trick, but not very useful. Yes, Google Goggles, I know I’m at the Leaning Tower of Pisa. Yes, that is the Mona Lisa. Google Goggles, you’re very clever!
Now British data scientists have found a new way to guess your current location without looking at your current photos at all, instead using photos you’ve taken in the past.
The study, published earlier this month in Royal Society Open Science, analyzed a dataset of 8 million photos taken in the U.K. from 16,000 Flickr users, combed it for migratory patterns, and came up with a set of formulas that compute the probability of any given photographer appearing in a given location at a given time.
The resulting patterns were fairly obvious: the largest patterns of movement are between London and other major cities like Glasgow, Cardiff, and Birmingham, and otherwise correlate highly with distance. In other words, people tend to move to places that are big and/or close. Not exactly groundbreaking news.
What is interesting is the algorithm’s power to adapt. Whereas previous methods of studying human mobility have relied on census data and immigration statistics, culling data from photos on Flickr and other social media would let prediction algorithms discover new patterns and forget old ones without waiting for “official” data.
National Geographic cited the technology’s potential for predicting traffic patterns or the spread of a deadly virus. But should we be concerned about location prediction being used for more nefarious purposes, like surveillance?
Not especially. The kind of prediction described in the paper isn’t perfect. It can only estimate the probability of you appearing in a given location. And unless humans evolve into cyborgs, that probability will never be 100%. Also, location prediction only works with if your photos are geotagged, which is pretty easy to disable in Flickr’s “geopreferences” pane.
Still, it’s a good reminder to check those preferences, and anyone who is worried about photos betraying your location can make sure that location never gets uploaded in the first place. Here’s how!
Open the Camera app, tap the Settings icon and toggle “Save location” off.
Go to Settings > Privacy > Location Services and toggle “Camera” off.
Most digital cameras, if they’re location-aware at all, have an option to keep GPS out of the metadata for each photo. If not, most importing software has an option to strip location data during import.
And if that fails, you can always do it on your computer!
Right-click on a photo and go to Properties > Details > Remove Properties and Personal Information.
Export the photo using iPhoto without checking the box to include location information, or use a third party app like Exif Remover.