I often wonder where I had been standing when I took a picture, and what was around me. I’m getting close to 40,000 images in my Aperture library, and so many locations are now lost in the hazy reaches of my long term memory. There’s a solution to this problem – geotagging – embedding location data in the EXIF tags of photos, and the good news is that it’s getting more and more popular these days. So popular that Nikon has released a dedicated GPS tracking device that looks pretty slick and interfaces directly to the newer DSLRs. The bad news is, that like all of Nikon’s branded accessories, they want an outrageous price for it: MSRP $249.99

The good news is if you’re willing to do a little extra work, and you have an iPhone 3G, you have already spent all the money required. First get a copy of EveryTrail for your iPhone, and head over to EveryTrail and setup an account. Load up the application, associate your account and do a test trip to make sure everything works as expected. Once the trip is saved and uploaded to the EveryTrail server, you’ll get an email with a link to the trip on a google-maps mashup. At the bottom of the screen is a “Download GPX” option. This is the GPS data in an XML feed, suitable for use in the last step.

Once you know it works, and you are comfortable with the app’s interface, get ready for your photo tour. Make sure that the time in your camera matches the time on your iPhone. The iPhone can set it’s time automatically so you don’t have to do this before you leave your house. In the field, launch the app, start recording location data, and use the lock button within the EveryTrail app. (This keeps your phone from going to sleep and losing track of where you are.) Take as many pictures as your battery and memory card(s) will allow, unlock EveryTrail, and go home. On the drive back, go ahead and upload the saved GPS data to the EveryTrail service.

You’ll need another freeware application for the last step – GPSPhotoLinker – and the GPX file you can download from your saved trip on EveryTrail. Simply plug your camera into your Mac, and it should show up as a USB drive. Load those pictures into GPSPhotoLinker (with the “Load Photo” button on the right), as well as the GPX file (with the “Load Tracks” button on the left), go into Auto mode, and select “Batch Save Photos”. It will grind away for a few minutes, and embed GPS data into the files on the memory card.

Now, when those images are brought into Aperture or iPhoto, they will have the location information stored within. When you upload them to flickr, FaceBook, or Picassa, etc, people will be able to see where they were taken.

Note: This also works with the 3GS, but not so much with the original iPhone or the iPod Touches. You really need the GPS in this case – the SkyHook wireless location service just won’t cut it for what we’re trying to do. And yes, I’ve been muling over this post for awhile, which is apparent if you look at the post ID for this post (868) vs the previous post (1014).