In a few years, cameras will all have single chip GPS units in them. They’ll tag their photos with the location where you took them as a matter of course, like they already tag the time and date.

Some of us are unwilling to wait a few years. I’m sure you, like me, have sat down with a map and a stack of holiday photos and thought “OK, where on earth was that building?”. My current project of scanning and annotating hundreds of old family photos would be so much easier if I could have some clue as to at least the location and the year.

Which is probably why Sony have just launched a rather neat keychain GPS. No display, not many controls, you just clip it to your bag and forget about it. At the end of the day you connect it to the computer, run some software, and your photos are annotated with location information.

However, you don’t need a special Sony GPS for that. There’s a handy Mac application called GPSPhotoLinker that will download the automatic track data from a Garmin or Magellan GPS, cross-reference it with the timestamps on a bunch of photos, and re-write their EXIF information to add longitude, latitude, city, state and country.

We tried it out in Austin on Wednesday. It seems to work quite well, so we’ll take the GPS with us when we go to Germany.

As well as embedded EXIF tags, known as geocoding, there’s also the cruder hack of geotagging, where you add the latitude and longitude as Flickr tags. While this avoids the problem of dumb software stripping EXIF information, it messes up your Flickr tags page and relies on Flickr, so I’m not keen on it. I want my metadata in the file with the image, where it belongs.