You’re probably familiar with the metadata that’s embedded in digital photos—information your camera automatically adds to each image file—such as the time stamp, camera model, lens and camera settings and more for every shot. What most digital cameras don’t log automatically is where you shot each image. That’s where geotagging comes in. With a handheld GPS unit and appropriate geotagging software, you can “tag” each image with its latitude and longitude information. Some systems also will record elevation and even the compass direction at which the camera was pointed for the shot.
One obvious reason is so you can find the precise spot again. If you want to return to a particular place at another time or season when the light will be different, you’ll know exactly where to go—especially useful when you’re in unfamiliar terri-tory. It also adds an extra dimension to your photo travelogues.
Plus, in the digital world, it’s easier to share our photography. Including location information when you post photos in galleries and contests can inspire others to visit those locations for great photos of their own.
The most practical reason, though, is organization. Apple’s Aperture 3 and iPhoto ’09 will automatically map your photos and translate your GPS coordinates into searchable place names. Google’s Picassa and sites like Panoramio.com also have geotagging features.
A handful of cameras have geotagging GPS units built in, which makes the process simple: Shoot your photos, and the location data is automatically added to the metadata for each image as you shoot.
If your camera doesn’t have this capability as stock gear, there are a number of geotagging GPS accessories available that connect to your camera. These also record location data as you shoot each image—just like a built-in GPS, only you have to acquire and carry the separate unit.
With any digital camera, you can use a handheld GPS to record location data, then use geotagging software to sync the GPS data to your photos in your computer. Exact details vary from software to software, but basically, you switch on the GPS, make sure it has acquired satellites and is ready to go, then start shooting. When you’re done, open your geotagging software, download the photos from the camera and the tracklog from the GPS, and let the software tag the images. The key here is that your camera’s date and time need to be in sync with your GPS receiver so the software can match the time stamps on your photos to those of your GPS positions.
The most labor-intensive way to geotag your photos has the advantage of working with any GPS unit that has a display panel, and any digital camera: Each time you take a photo, photograph the screen of the GPS to record the location data. Then, when you get home, manually enter that data in the EXIF metadata for the image in your computer—no special software required.
Some geotagging software lets you assign a location to an image by navigating to the location where you took it on a map. This is best done when you originally download the photos, of course, and can remember where you shot them.
Red Hen Blue2Can
Compatible with select Nikon DSLRs, one part of this two-piece unit plugs into the camera’s 10-pin connector, while the other is positioned to see the GPS satellites and transmits data by built-in Bluetooth connection. Photos are geotagged as you shoot them. www.redhensystems
The 12-megapixel CL65 can shoot 720p HD video, has a 5x zoom lens and Bluetooth connectivity, and features a built-in GPS for geotagging. www.samsung.com
Sony Cyber-shot HX5V
Featuring a 10.2-megapixel Exmor R CMOS sensor, a 10x, 25-250mm equivalent zoom lens and AVCHD video capability, the HX5V also has integrated GPS and compass for geotagging. www.sonystyle.com
Eye-Fi Explore X2 8GB Memory Card
This unique unit combines a Class 6 SDHC memory card with Wi-Fi wireless photo and video transfers from your camera and the ability to record location data via WPS from a nearby Wi-Fi hotspot. Upside: Simple, works with any SD-compatible digital camera. Downside: Works only in range of Wi-Fi hotspots. www.eye.fi
Microsoft Pro Photo Tools
A free download from Microsoft, Pro Photo Tools lets you import GPS track data, automatically tag both JPEG images and RAW files, and reverse-geocode (translate) the data to place names (country, state, city and even address). www.microsoft.com
There are 29 NavStar GPS satellites orbiting the Earth twice a day some 12,000 miles above. Each satellite sends UHF radio signals that can be picked up by GPS receivers down here. The radio signals travel at a specific speed, and by measuring the time it takes signals from different satellites to reach it, the GPS unit can determine its distance from each satellite. It then uses trilateration (essentially, 3D triangulation) to calculate its position on the Earth’s surface (to within about 15 meters with typical handheld GPS units).
It takes a while for a GPS unit to acquire the minimal number of satellites needed to do its thing, and this can be a problem for “decisive-moment” situations. You still can take the photo, but the location data won’t be recorded if the GPS unit isn’t locked on.
We don’t have room here to cover all the details of GPS operation, and knowing all the details isn’t necessary to geotag your images. If you want the full story, google “how GPS works,” and you’ll find some excellent information.