The Secret Data Hidden in Your Snapshots

Oct 31, 2014

You'll often see this maxim posted in national parks: "Take only pictures, leave only footprints." But what if your photograph IS your footprint, and it can be tracked by anyone who might follow it?

German photographer Philipp Schmitt visualizes those digital footprints in his "Location-Based Light Painting Project." In his small town near Stuttgart, he sets up a 35mm digital camera and, with long-exposure black-and-white images, "maps" each geotagged photo taken around the touristy Heilig-Kreuz-Münster city center.

How does he do it? Fluent not only in English and German but in numerous coding languages, Schmitt created an iPhone-based app that pinpoints his location using Global Positioning System (GPS) coordinates, then scours the web to cross-reference those bearings with any "geotagged" photographs taken there. (Such photos have GPS information embedded in the image file or were later attached to a map, like these examples from Google Panoramio and Flickr.) When his physical path intersects with the geolocations of those images, his smartphone emits a sound. The sound, in turn, triggers a strobe light attached to the phone. Schmitt stalks his predecessors around the scene, effectively "painting" the area with the tiny lights, while a camera on a tripod records his movements. In the end, he geotags the resulting photos—which are themselves aggregations of geotagged photos—so that, as he explains, "they add to the mass of noise they’re documenting."

The first series of photographs Schmitt made during the project are nighttime cityscapes; a glowing orb marks each of the original photographers' vantage points. The second series goes one step further, employing a long-exposure technique to show the "ghosts" of the photographers, using a second person as a stand-in. Contemporary large-format photographer Matthew Pillsbury also uses long-exposures to visualize the inhabitants of public and private spaces, while artist Corinne Vionnet similarly aggregates existing color photographs of tourist locations around the world found online and layers the shots (taken from slightly different perspectives and times of day) in the computer. Philipp Schmitt, however, is the first to use an app to fire lights which symbolize the footsteps of those who once visited a location.

Schmitt, a student in Interaction Design at Hochschule für Gestaltung Schwäbisch Gmünd in southern Germany, got the idea from watching out his home window as tourists photographed the town church fountain. He started wondering, "How many photos have been taken of that stupid fountain?" Schmitt explains:

The amount of existing photos is just extraordinary. According to Wikipedia, Google Panoramio alone archives more than 65,000,000 geotagged images. Popular landmarks are so thoroughly documented by photographers that PhotoSynth can create 3D models of these places just using pictures.

This is all well and good when you want your location to be known, when you are aware that—via the particular camera or smartphone you use—your GPS coordinates are being logged, mapped, and disseminated globally. What if you aren't aware? Schmitt's strobes also cast light on a darker issue: online privacy. How much information should you share and when, in an age when oversharing on social media can result in a lost job when recruiters search your profile prior to your interview, when sites like Facebook track the clicks of your digital footprint and share them with advertisers, when Tinder users are scouring your photos for personal details, and when geotagged images in a Craigslist post can reveal the layout and location of your home and all of your personal possessions. (Money details the repercussions of your personal data falling into the wrong hands as it relates to recent data breaches and what you should do about it here.) In the case of geotagged images, it is possible to strip this data from your image files by adjusting settings on your camera and phone and opting out of attaching it when you upload them publicly.

Right now, it's just a photographer or two who may be peering in your apartment windows like Arne Svenson as he "tests the limits of privacy," stealing your Facebook photos like Paulo Cirio and the team of Jonathan Pirnay and Jörn Röder, or following in your geotagged footsteps (almost in real time, if he so chooses) like Philipp Schmitt. Still, that's just one small leap away from electronic billboards targeting you in public spaces based on personal or geotagged data. Schmitt has already open-sourced parts of the code "to encourage people to do their own location-based light paintings." Feel free to download it here, then geotag your images and add to the noise. Just make sure if you leave a trail, it's one you don't mind others following.

This is part of The Photo Bank, a section of dedicated to conceptually-driven photography. From images that document the broader economy to ones that explore more personal concerns like paying for college, travel, retirement, advancing your career, or even buying groceries, The Photo Bank will showcase a spectrum of the best work being produced by emerging and established artists. Submissions are encouraged and should be sent to Sarina Finkelstein, Online Photo Editor for

More from The Photo Bank:
FREE Money! (If You _ _ _ _ It)
Looking at ‘Rich and Poor,’ 37 Years Later
When the DynaTAC Brick Phone Was Must-Have Technology

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