Definition: Geotagging a digital photo or other object on a Web site or in a document refers to the attachment of geographical identification data. For example, a geotagged digital image would include precise latitude and longitude coordinates, and may also include altitude and other information. This permits the image or other object to be easily and precisely positioned on a map, putting the geotagged image into context, and making it more easily searchable. A number of popular Web sites permit the upload of geotagged photos, and digital cameras may include geotagging capability, or may be fitted with accessories that automatically geotag photos.
Geotagging (also referred to as geocoding) essentially involves "tagging" something like an image or Web site with location data. It doesn't necessarily involve GPS, however it usually involves latitude/longitude coordinates so GPS is a logical tool for geotagging.
Most recently, geotagging has become a popular way for photographers to identify and record where they snap their photos. Whether it's a professional photographer or just an avid amateur who loves traveling or the outdoors, more and more people are discovering geotagging every day.
Geotagging can be a great way to organize images. When you combine geotagging with online mapping services, you can imagine how developers can come up with some creative options for using and publishing the data. For example, Flickr has some interesting tools for leveraging geotagging. Vacationers can now see a "map view" of all their images. Hikers can keep track of favorite routes for later use or to share with others.
Using geotagging technology, you can also "geoblog" by attaching a blog post to a specific location through a geotag. In the latter example, blog posts could be organized (and selected) by location vs. by topic or date. This is great for people who already like to blog about their vacations, for example, and want to share images this way as well.
There are various pieces of equipment that you can attach to your camera to record GPS coordinates and begin geotagging. One such product is the "Kato" from Geotate. According to Geotate, the Kato requires "zero integration" with the camera- recording the information for each picture, but not requiring a transfer of the information until the pictures are downloaded on to your computer.
However, iPhone users are in luck. The 3G iPhone with GPS also has geotagging capabilities. GPS-enabled camera phones with geotagging software will eventually lead to a real surge in geotagging. Many people have not yet discovered geotagging but it's only a matter of time. Combined with phone GPS navigation, it will open up a whole new range of possibilities within online and mobile social networking.
What is Geotagging a photo?
Geotagging is the act of associating geographical / GPS co-ordinates with a photo, normally by embedding the data in the EXIF information stored in several image formats - for example, alongside the ISO, shutter speed and aperture settings.
There are two ways geotagging is performed: with a suitable camera (such as the Nikon D200) and an adapter for a GPS unit, you can record it straight to EXIF at shooting time. Alternatively, you can replay the the track and align the timestamps to see the nearest point to the time at which you took each photo. Latter one is preferred, because not only is it cheaper, but it looks a whole lot easier than carrying around huge adapter cables.
Adding location data to photos at source saves me the hassle of browsing around on multimap trying to find exactly where you were at the time; the data is there, accurate to maybe 5s and a few metres.