Global positioning is a useful technology. It can be used to pinpoint your current location - great if you're lost - and, of course, help you find the fastest or least congested route from A to B.
But satnavs have long been criticised for our loss of basic map-reading skills, for distracting drivers and, not least, for their nagging voices. Indeed, a recent survey conducted by Direct Line reveals that 300,000 UK drivers have either crashed or had a near-miss because they were concentrating on the satnav rather than the road.
So it's just as well that GPS isn't confined to satellite navigation devices. Over the following pages, we'll be looking at a different use for the technology: geo-tagging.
Digital cameras and mobile phones are increasingly able to geo-reference information and pinpoint our location. It's now possible to ‘geo-tag' photos before uploading them to the web, allowing Google Maps, Google Earth and similar mapping applications to display the exact location that an image was taken.
For Ewan McGregor and Charley Boorman, obtaining advance visual information about where they were bound was invaluable on their ‘Long Way Down'. For the rest of us, such information can be useful for holiday planning and general reference.
You can check out photos posted by other geo-taggers of holiday locations, hotels or campsites before you head there, or upload your own images so friends can track your trip while you take some time out from the rat race.
You'll need a GPS-enabled device to allow a location to be embedded into the image file. If your existing mobile phone or camera doesn't feature such technology, it may be compatible with an external GPS unit.
You'll also need to sign up to a geo-tagging site such as Panoramio, which we've used in the following walkthrough.
1. Panoramio offers 2GB of storage for your digital images. Here, snaps can be tagged and then displayed on Google Maps, where they will appear whenever someone visits that location. Head to Panoramio and set up an account. Enter an email address, username and password.
2. It's unlikely that you'll have the hardware necessary for embedding geographical information into an image file to hand. Instead, upload your photos to Panoramio and add geographical details from here. While the site lacks a batch uploader, you can browse to and initiate a second upload while the first is in progress.
3. Once your images have uploaded, Panoramio offers to ‘Map this photo'. Enter the street name or place where the image was taken and hit Next. A list of possible locations will be displayed underneath the box; click the correct location and a Google Map featuring an aerial view of that place will be displayed.
4. Adding your photos to a virtual map isn't an exact science, so you'll probably need to fine-tune their positioning. Use the zoom slider and cursor button to navigate in Google Maps. Drag the red marker to the correct area and press ‘Save Position'. Repeat this process for all your images and then click Finish.
5. Thumbnails of all your uploaded images can be found under the Your Photos tab. Click a thumbnail image to view it full-size. This will also display a Google Map with the image's location clearly marked, alongside small thumbnails of any pictures taken by other Panoramio users in the same area.
6. Another way to view your own or others' photos in Google Maps is to click the Places tab, enter a location into the search box and press ‘Search Place'. Panoramio will display a list of possible matching locations; select one and you'll see a Google Map with images captured in that location scattered across it.
7. Use Panoramio's tabs to view the most popular, your own or all images tagged to that location. Click any thumbnail image to view it full-size. To share Panoramio images with friends, click the Your Photos tab and copy the URL displayed in the address bar. Paste it into an email and forward it to your friends.
8. Panoramio lets you view images in Google Earth, too. Head to earth.google.com, select your location from the drop-down menu, then agree to the terms and conditions and click download. Open the shortcut on your desktop and click Install. Click Finish to complete the setup, then launch Google Earth.
9. Back at Panoramio, click the Your Photos tab and then choose to see the image in Google Earth. In the resulting pop-up window, make sure that the ‘Open With' option is selected and that Google Earth is the program selected in the drop-down menu. Finally, click Open.
10. In Google Earth, a photos folder will have appeared under the Places section on the lefthand side of the display, containing your images and the location where they were captured. Double-click this folder and Google Earth will zoom in and display an aerial picture of the area the photographs were taken in.