Hands on: Location, location, location

We're going to take a Hands On look at geotagging. This is the process of adding positional data, usually but not necessarily obtained from a sat-nav device, to digital images. I’ve been experimenting to try to find the best way to do the job.

I’d been manually adding latitude and longitude data to photos using Google Maps by going to http://maps.google.co.uk, zooming in on the required location and copying the data from the ‘link to this page' link.

For a few photos this approach is workable, as long as you’re familiar with the area in question. But it’s labourious and time-consuming. Even if you don’t have a GPS receiver, an increasing number of photo-editing applications provide the means to add geopositional metadata to your photos.

Google Picasa lets you Geotag your photos using Google Earth. Selecting ‘Geotag with Google Earth’ from Picasa’s Tools > Geotag menu launches Google Earth and a Picasa window with your image thumbnails appears in the lower-right corner of the screen. Then you simply select the shot, find the location using Google Earth’s navigation controls and press the Geotag button.

Using maps to geolocate photos makes things easier, but it’s still time consuming and error-prone. It’s usually straightforward to geolocate photos shot in an urban environment where you have plenty of buildings and landmarks to help you out. But finding rural locations can be a different matter. One field can look much like the next, and what if you want to geotag photos that were taken on a cruise or in flight?

Go with GPS
The only answer to this problem is to carry a GPS receiver with you and use software on your PC to match up your photos with location data from the GPS track log.

Digital camera and photo accessory manufacturers are becoming aware of the interest in geotagging and it is only a matter of time before more sat-nav device manufacturers follow suit. If you’re looking for a dedicated geotagging sat-nav, there is a handful of units from which to choose, including Sony’s GPS-CS1. Though designed for the CyberShot range, it can be used with any camera. There’s also the Gi STEQ Photo Tracker and Jobo’s Photo GPS, which fits into your camera’s hot shoe.

The devices work in the same way. Time-referenced positional data is recorded in a track log file, which is downloaded to the PC and cross-referenced with images via the Exif time information recorded when they were taken.

If you have no other use for a sat-nav device, then these are small, inexpensive and doubtless do a good job. But if you already own a GPS receiver, or are thinking of getting one for in-car use, hiking, cycling or other outdoor pursuits, then you can also put it to geotagging use.