Geotagging

I do geocaching. And naturally, i make photos during my trips. So why not connect the two? What if I could tag my photos with the coordinates they where shot on? My camera does not have a built in GPS receiver, but that is no problem.

My GPS is a Garmin hand held device, with USB port. I’ve chosen GPSBabel, as it is said to work well with Garmin devices. Unfortunately, there is a little problem with USB modules, but a solution can be found here. Just a note: I did the Ubuntu Dapper solution, and had to restart after the editing/creating of the files. No kernel recompiling was necessary.

For USB capable Garmin devices, type in the following command:

$ gpsbabel -t -i garmin -f usb: -o gpx -F tracklog.gpx

This will download the tracks from the GPS to a file called “tracklog.gpx”.

The EXIF metadata section of a photo holds information on the creation time of the photos (among other things), (just make shure that the clock in your camera is adjusted well), so the time stamp of every photo is to be checked against the tracklog, and if a track point with the same time stamp exists, then the coordinates of the trackpoint are to be written to the GPS section of the metadata of the photo.

This is what GPS Photo Correlate does. And it comes with a GUI too. It is capable of interpolation between trackpoints, so if the time stamps are not exactly the same, it will correlate from the coordinates of two adjacent points for the time stamp of the photos. Really easy to use. The only flaw – for me – is that it seems to be unable to write to DNG files.