Wednesday, November 20, 2013
Are you one of those people who takes selfies and posts them to your Web page or Facebook? Do you use your cellphone to photograph your children and upload images for friends, family and others to see?
You might want to reconsider.
Smart phones and other mobile devices are recording not only the image, but a host of geographical identifiers that can be accessed by savvy Internet users. The data is called a geotag.
Smart phones and mobile devices are now routinely recording the latitude and longitude, and sometimes altitude, bearing, distance and place names. Savvy Web users can access that data, and more, from the photos you post online.
The process of geotagging allows Web users to replicate images they see.
For example, say you take a great sunset photo overlooking Liberty Bell Mountain and somebody else wants to take the same photo. By accessing the geotag, they can see the time, date and location from where you took the photo. They can also see what your camera settings were and the direction and angle at which the camera was positioned.
They follow your footsteps, and your geotag, and obtain the same great photo. No harm done.
But take the geotag information a step further.
Somebody wants to know where you or your children are. You post a photo of your child at their school, but the image doesn’t show the name of the school.
Someone with knowledge on how to access the geotag now has time, date and coordinates of the location from which the photograph was taken. They can also see find data that will pinpoint exactly what angle you pointed the camera.
By plugging in the latitude and longitude in any number of websites, they can use geotag data to get a map location and probably the name of the school where the image was taken. That geotag has now given somebody you may not know – or someone you don’t want knowing where you are – access to information about you and your children.
Since GPS data is based on measurements related to satellites, geotag data is embedded even when you’re in areas without cell phone service. Scary thought, huh?
Geotags are commonly found on photos taken today with devices that have GPS systems installed. Almost everything we use today in the mobile world has some type of GPS system. The system is needed – indeed mandated by law – for wireless phones to provide precise location information for the 911 system.
Just turning off your GPS service doesn’t necessarily stop mobile devices from embedding positioning data in your image, since your device is constantly recording GPS data for the 911 system. As a cellphone photographer, take steps to protect information you don’t want others to have. Your privacy is at stake.
Roger Harnack is the editor and publisher of The Chronicle. He can be reached at 509-826-1110 or via email at firstname.lastname@example.org.