Ipsa scientia potestas est

While nearly every iPhone 3G user is aware of the embedded GPS functionality, I imagine most users don’t realize that if you allow the iPhone’s camera application access to your “location”, current GPS information is embedded in the image you capture as EXIF data.  This is a process called “geocoding”.

For those of you who do not know what EXIF data is, EXIF stands for “Exchangeable image file format.”  Essentially it is text, words, characters or information stored inside an image which is usually present to assist devices/applications in understanding more detail about the image than just how it looks.

Details like camera type or aperture are just two of an infinite number permutations available.  Usually this data is represented as name:value pairs.  For example:

MIMEType => image/jpeg
Make => Apple
Model => iPhone

So what exactly happens when you select “OK” when the iPhone camera prompts you for location usage?  (Which also happens to be the default selection.)  The iPhones camera accesses data from the built-in GPS and writes your current location into the image as GPS coordinates.

Bear in mind that once you select “OK” the camera will always embed the data until you reset or disable location services.

Good idea?  Bad idea?

The reality is it really depends on subject matter of the image.  Let’s say the image is of you performing a nefarious deed: You’ve just documented the time and place with photographic evidence of your deed.  Talk about damning evidence.  What about a good idea: You take a picture while on vacation and want to document your exact location so others may see what you’ve seen.

Bad idea: You’re a Realtor trying to sell a home without disclosing its location. You take pictures and put them online to entice buyers. It makes no difference if you don’t disclose the street address because you’ve just told the world with GPS data exactly where that home is situated.  Epic move.

Good idea: You’ve just stumbled across the best Japanese restaurant in the known universe and want to share with everyone. You snap the picture, send it to everyone who cares and they now have everything they need to find the place.

Bad idea: You’ve cheated on your loved one by taking hot pictures of your mistress doing things illegal in 37 states and you’ve brilliantly opted-in for geocoding.  Your clued-in girlfriend/wife finds the images, checks the GPS coordinates and pays your sassy tart a visit.

Good idea: You’re hopelessly lost in the wilderness by yourself and somehow you have Edge or 3G service.  Your vocal chords are broken by a tree branch and the only hope is to take a picture and email it to someone who can help.  You don’t know where you are, but the GPS does.

So what does this data look like?  What are the name/value pairs embedded in the EXIF data?  The following data was pulled from an image I took the other day:

Aperture => 2.8
BitsPerSample => 8
ColorComponents => 3
ColorSpace => sRGB
CreateDate => 2008:11:29 12:26:22
DateTimeOriginal => 2008:11:29 12:26:22
Directory => .
EncodingProcess => Baseline DCT, Huffman coding
ExifByteOrder => Big-endian (Motorola, MM)
ExifImageHeight => 800
ExifImageWidth => 600
FNumber => 2.8
FileModifyDate => 2008:11:29 14:41:38-06:00
FileName => web.jpg
FileSize => 149 kB
FileType => JPEG
GPSLatitude => 9 deg 42′ 15.28″ N
GPSLatitude (1) => 9 deg 42′ 15.28″
GPSLatitudeRef => North
GPSLongitude => 1 deg 40′ 5.20″ E
GPSLongitude (1) => 1 deg 40′ 5.20″
GPSLongitudeRef => East
GPSPosition => 9 deg 42′ 15.28″ N, 1 deg 40′ 5.20″ E
GPSTimeStamp => 12:26:18.07
Gamma => 2.2
ImageHeight => 800
ImageSize => 600×800
ImageWidth => 600
JFIFVersion => 1.01
MIMEType => image/jpeg
Make => Apple
Model => iPhone
ModifyDate => 2008:11:29 12:26:22
ResolutionUnit => inches
ResolutionUnit (1) => inches
XResolution => 72
XResolution (1) => 72
YCbCrSubSampling => YCbCr4:2:0 (2 2)
YResolution => 72
YResolution (1) => 72

So really you can see here that a lot of detail has been added, including GPS coordinates.  The name:value pairs we’re concerned for article relevance are as follows:

GPSLatitude => 9 deg 42′ 15.28″ N
GPSLatitude (1) => 9 deg 42′ 15.28″
GPSLatitudeRef => North
GPSLongitude => 1 deg 40′ 5.20″ E
GPSLongitude (1) => 1 deg 40′ 5.20″
GPSLongitudeRef => East
GPSPosition => 9 deg 42′ 15.28″ N, 1 deg 40′ 5.20″ E
GPSTimeStamp => 12:26:18.07

While there is a little bit of redundancy, you can see that the location and GPS timestamp is embeded.  Using a tool like Exif Viewer for Firefox, you can not only view the GPS data, but also link you right into Google Earth to jump to the coordinates.

So what is the moral of this story?

Every piece of technology can be used for good or evil. Fire can be used to cook meat or set huts ablaze; a knife can be used to gut a fish, or a human.  Handguns can be used to fend off wolves or bears in the wild Northwest Territories, similarly a handgun may also be used to whack a Consigliere from a Borgata of which you’re not too fond.

Same rules apply with technology.  Unwitting individuals will take photos of places/settings/people which really shouldn’t be geocoded.  Will they know any better?  Probably not.