How iPhone 5 Geo-Tags Photos

My Canon DSLR, like most cameras, does not have a built-in GPS and cannot geo-tag photos.

I experimented on a recent trip with shooting a reference photo on my iPhone with the Camera app at each location where  I wanted to record the location.  What did the iPhone capture?

Here is what the relevant EXchangeable Image File (EXIF) metadata looked like on a JPEG photo file, as revealed by Photoshop CS4.

<exif:GPSLatitude>37,51N</exif:GPSLatitude>
<exif:GPSLongitude>79,4.66W</exif:GPSLongitude>
<exif:GPSAltitudeRef>0</exif:GPSAltitudeRef>
<exif:GPSAltitude>38327/71</exif:GPSAltitude>
<exif:GPSTimeStamp>2013-05-23T22:35-05:00</exif:GPSTimeStamp>
<exif:GPSImgDirectionRef>T</exif:GPSImgDirectionRef>
<exif:GPSImgDirection>23937/166</exif:GPSImgDirection>

Waterfall GPS metadata from File ViewerThis markup language is a bit obscure and some of it, like altitude and bearing, require some addition calculation to get a useful number.  Other software packages, including more recent versions of Photoshop, interpret and present the data in a more user-friendly format. Here the GPS meta-data from the same photo presented by the program File Viewer, a handy desktop app that lets me drag any type of file into it’s window to see the file’s metadata.

Even this presentation needs some massaging.  If you want to see where I took this picture using Google Earth, you would have to know that “LongitudeRef: W” requires you to put a minus sign in front of the longitude.  If you wanted stand at the site and face the direction in which I snapped the picture, you would have to know that “ImgDirection” combines with “ImgDirectionRef” to specify 144.2 degrees off true north.  The altitude is presented without units, you would have to know these are meters – the EXIF metadata standard – and not feet.

I wanted to post the photo here so you can inspect its metadata for yourself, but found WordPress is on of several applications that don’t preserve geo-metadata.

 

One thought on “How iPhone 5 Geo-Tags Photos

  1. Grant

    Good work, keep going with it. If it’s possible to use an iphone to geotag I’ll get one. Maybe you should create an app that does just that!

    Grant

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *