Geotagging: what your photos reveal about where you live
In this post we’ll show you how to ensure that the pictures you upload to social networking platforms are wiped clean of any personal information that could reveal your – or your cat’s – exact geo-location.
A project out of the University of Florida entitled I know where your cat lives highlights how easy it is to identify people’s home address based on the pictures of their cats, uploaded to popular photo sharing platforms such as Instagram or Flickr.
I know where your cat lives
Researchers from the University of Florida located, with an accuracy of 7.8 meters, the exact place where pictures tagged with the word “cat” were shot.
They started by extracting metadata (including the latitude and longitude of where the picture was taken) from a sample of 1 million images, accessible from publicly available APIs from popular photo-sharing websites. The photos were then run through clustering algorithms with the help of a supercomputer. The researchers then created a website, where cat images were superimposed with GoogleMaps, pinpointing their exact location. Well, that’s just purrfect…
I know where your cat will be 24 hours from now
Okay, chances are even you don’t know that (much less your cat). But that’s where the technology is heading. Two years ago, a team from Birmingham University developed an algorithm that successfully detected where a test sample of people were going to be 24 hours in advance… How did they do it? By combining information on where they’d been (think of every time you checked into Foursquare) with the past movements of contacts in their Smartphone’s address book.
How your address finds its way into your pictures
When taking a picture, information is stored in the form of Exif tags. These detail the camera’s model, the image’s resolution in pixels, the time/date the picture was taken… This type of metadata is typically fairly innocuous. However as Smartphones now include in-built GPS, Exif tags frequently include the longitude and latitude as well. This functionality is referred to as Geotagging.
How to disable geotagging on your Smartphones
As your GPS is necessary for certain applications we’re just going how to show you how to remove geotagging when taking pictures.
If you’re an Android user:
- Access your phone’s camera application
- Select “Store location” on the left hand side, below “color effect”
- Switch off the geotagging
If you’re an iPhone user:
- Go to settings
- Select “Privacy”
- Select “Location Services”
- Find “Camera app” and switch it off
How to remove geotags from existing pictures
To remove geotags from all your pictures, you can do so with free software.
- For Windows users:
Try Microsoft Pro Photo Tools version 2. This free tool enables you to easily edit or delete Exif tags from your digital photographs, including the GPS location.
It is also possible on Windows to remove Exif tags manually without installing additional software. For an overview of the process with step-by-step screenshots, please visit: www.technorms.com/38749/remove-personal-exif-information-from-digital-photos
- For Mac users:
Although privacy concerns over metadata is not new, the project I know where your cat lives did a great job of raising awareness for the problem. We recommend that you think carefully about what information you’re going to share (many users contacted the researchers at the university of Florida and asked them to upload their cat’s pictures and location to their map). If you are uncomfortable with sharing your location, please be sure to remove the Exif tags.
P.S. Avira developed a free tool to prevent companies for tracking your web activities. If you would like to learn more, please visit: www.avira.com/en/avira-browser-safety
This article is also available in: German