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Geotagging your digital photos

Struggling to keep control of your growing collection of digital photos? Breathe easy — you're not alone.

Struggling to keep control of your growing collection of digital photos? Breathe easy — you're not alone.

With digital cameras making it easy to take images of just about every aspect of daily life, budding photographers are left wrestling with the best way of labelling them so they can be saved and shared with friends and family.

While file names, key words and captions can help with the process, a new technique promises to change the way photos are stored and viewed — it's called geotagging.

As the term suggests, geotagging involves attaching tags to digital photos that describe exactly where they were taken. It's a simple concept, but it opens up an exciting range of new ways in which such tagged photos can be used.

How geotagging works
Geotagging involves finding the latitude and longitude of the place a photo was taken and embedding this information in the photo using a standard format called EXIF (Exchangeable Image Format).

Used by most digital cameras, EXIF stores everything from the time and date an image was taken to the type of camera used and its exposure settings. Geotagging just adds a little more data into the mix.

Labelling your images in this way provides another way to categorise them. Rather than trying to remember the date you took that memorable holiday to Queensland or the file names you used when downloading them, you can find your photos simply by searching for a particular location.

How to geotag images
There are a variety of different ways to geotag photos. The one you use will depend on the device you're using to take them and the way in which you want to make use of the finished product.

The most accurate method of pinpointing your exact location when taking photos is to make use of the Global Positioning Satellite (GPS) network that is constantly sweeping through the skies above our heads. By tracking multiple satellites and comparing the signals received from each, a GPS receiver can determine where you are on the surface of the globe to within a couple of metres.

But while GPS capabilities are already in widespread use in personal navigation devices, they're yet to make the move into digital cameras. The biggest challenge is to find a way to add the feature without sacrificing battery life or adding significantly to a camera's weight.

However all the major manufacturers are working on it and we can expect to see GPS-enabled digital cameras on the market within the next 12 months.

But, while you wait patiently for these new models to appear, there are some simple ways you can start geotagging your photos right now:

Sony's GPS-CS1
external GPS receiver

Use an external GPS tracker
If you're using a digital camera, one option is to also use an external GPS receiver. There are various models available but all fall into two main groups.

The first takes a note of your position using GPS and keeps a log in an internal file. By synchronising the clocks in both the device and your camera, a PC-based application can later match the time stamps on your photos with the tracker's record of where you happened to be. This data is then added to each photo as a geotag.

The second option, if your camera supports it, is to directly connect an external GPS receiver. This feature is currently available only in high-end cameras (such as Nikon's D3 and D300 and Canon's 40D), but means that GPS positioning details can be added as each photo is taken, ensuring locations are recorded accurately.

Apple's iPhone 3G features GPS

Grab your GPS mobile phone
Now that growing numbers of mobile phones are sporting GPS capabilities as well as digital cameras, it makes them a natural choice for the geotagging enthusiast.

Nokia Australia geotagging expert Bruce Webb says the onboard GPS receiver in models such as the N82 and N95 makes it easy to capture location data and add it to digital images.

"Sailors and truckies have been using GPS for years but now it's becoming popular for everyone and being used for applications such as photography," he says. "It will eventually become the norm to geotag all photos in the same way as people have added captions in the past."

Nokia plans to make the software needed for geotagging a standard feature of future phones. Users of a range of existing handsets need to download a small application and install it on their device. Once operational, the software checks for a GPS signal and, if available, automatically adds the appropriate information to each photo as it is taken.

Other handset makers, including HTC, Sony-Ericsson and Motorola, are expected to add similar offerings to their GPS-enabled handsets.

Geotag photos manually using Google Earth and Picasa

Do it manually
Another option is to wait until you've finished taking photos and add all the location details once you've downloaded the images to your PC. There are a variety of ways to do this, but one of the most straightforward uses a combination of Google's Picasa software and the company's Google Earth application.

After downloading your photos into Picasa, it's simply a matter of clicking on the tools tab and selecting the 'Geotag with Google Earth' option. This opens the mapping application in which you navigate to the place where the photo was taken. A single click then embeds the relevant latitude and longitude details into the photo's EXIF metadata file.

Sharing your geotagged photos
Once location details have been added to your photos, the real fun can begin. Geotagging opens up a raft of new ways in which your images can be shared with friends or put on show for the world to view.

Most popular internet-based photo sharing services support geotagged photos but two of the most popular are Yahoo's Flickr and Picasa Web Albums.

The Flickr web interface makes geotagging photos and placing them on a map about as easy as it can get. After uploading your photos to the site, it's simply a matter of zooming in to the exact location you took them on the map and dragging and dropping them into place. That's it.

Once on the map, your photos appear as small dots. Clicking on a dot opens a small preview window which you can click on again to access the full-sized photograph.

As well as your own photos, the map interface allows you to search through those tagged by other Flickr users. Navigate to a selected location and use the search function to find what you're looking for. Planning a trip to London? Enter the city name into the search box and a film strip of all tagged photos recently taken in the city will be displayed. Click on the photo and the location it was taken appears on the map.

One factor to remember when tagging photos in this way is privacy. While you may not mind if the world at large knows you had a burger in Leicester Square, you might not be so keen on everyone knowing exactly where you live and what the inside of your house looks like.

With this in mind, the site lets you choose a "geoprivacy" rating for each photo you upload. Options include allowing photos only to be seen by you, your family and friends or anyone who uses the site.

Picasa Web Albums
Like Flickr, Picasa Web Albums offers an easy point-and-click method of geotagging photos and adding them to a map. Each appears as a small thumbnail (rather than a dot) which opens to a larger preview pane when clicked.

Once tagged on a map, your photos can be easily shared with friends and family by emailing a link to your photo online album. This link provides the recipient with permission to access to the album where they can display all tagged photos on a map. If they have the Google Earth application installed, they can see all tagged photos on satellite images of the area.

As each individual photo is opened, a map showing the location it was taken is displayed alongside it, together with details such as caption and the date it was taken.

Such mapping features are a useful way to keep friends and family up-to-date when travelling. Why simply boast about hiking in the Grand Canyon on a postcard when you can send a geotagged photo of you doing just that and have it appear on a map?

The future of geotagging
With the mechanics of the process getting easier and more people discovering the benefits of sharing location information, geotagging is set to explode during the next couple of years.

With an eye on the trend, camera makers are working to incorporate GPS functionality into their upcoming models, streamlining the process of capturing accurate location information and embedding it in photos as they are taken.

"Right now the process is still somewhat manual, but when you can have photos tagged automatically, we will see the trend reaching new highs," says Google Australia's mapping expert Mickey Kataria.

Kataria points to his company's recent acquisition of Panoramio, a photo sharing site that has geotagging at its very heart, as a sign of what to expect. Panoramio has already amassed more than five million geotagged photos that can be viewed by anyone with a web connection.

Another site with a similar mission is Built on top of Google Maps, this site plots all photos as dots on the globe. Hovering your mouse over each dot brings up a thumbnail which opens to show the photo taken at that place.

The goal of such sites is to eventually provide a complete photo record of the entire globe, searchable via key words or maps. Once the concept becomes mainstream, the existing methods used for filing and sharing photos will seem positively antiquated.

5 reasons to try geotagging

  • Tagging photos with location details gives you another way to find them. Can't remember when you took that holiday to New Zealand? Find where you stayed on a map and your photos will appear.

  • Growing numbers of mobile phones have GPS capabilities, making geotagging of photos a one-stop process.

  • Rather than postcards, send links to your geotagged holiday photos to family and friends. They'll be able to monitor your progress and join the fun, albeit vicariously.

  • Want to recommend a new restaurant or bar? Why not send a geotagged photo of it to your friends. As well as seeing what it's like, they'll be able to find their way straight there.

  • Why keep your talent to yourself? Geotagging your photos and adding them to an online sharing site will allow anyone to check them out. Go on — get yourself a global audience!