Recording GPS data can be a fun as well as practical way of keeping a track of where images were shot. It becomes particularly useful when on your travels, shooting in various locations, as when you're back home and you have 300 shots to look through, you can easily catalog them into shoot locations by looking at the images' metadata where the GPS information is stored.
GPS devices such as Sat Navs, mobile phones and some Nikon compacts detect signals from a system of satellites in the earth's orbit and these signals are used to triangulate where the device is, its altitude and other useful information. This data is embedded into an image so the photographer can see where the camera was when the image was taken. Do remember that the GPS data recorded is of where the camera was located, and not necessarily the subject photographed. What we mean by this is that you could have used your zoom to fill the frame with a subject some distance away. By doing so you get a better picture but the GPS data recorded won't be accurate for the location of the subject, instead it will record where you were stood with the camera.
As mentioned, some cameras, such as the Nikon COOLPIX S9300, S9500 and P330, have built-in GPS, while other cameras, including the Nikon 1V1 and Nikon DSLRs, can be fitted with GPS unit accessories to records GPS data.
If you want to keep a more visual record of where images were taken you can use world maps to keep a track of the destinations you've shot images in and this is known as geotagging.
Maps can be found on some photo upload sites as well as in software such as Lightroom and ViewNX2. Some Nikon cameras such as the COOLPIX AW100 also have maps built-in. This particular model has a large map library and they allow the user to track and log their daily travels. When the user views the map, an icon will show the location logged as well as thumbnails of photos taken in that area.
As well as keeping a record for yourself, other photographers may find the information useful as they can find the same spot, thanks to the GPS data, and shoot their own image of the same subject. If you don't want to share this information make sure you remove it from the image's metadata before posting online.
Turning your Nikon's GPS on is a straight-forward process. You need to make sure the date and time is set correctly on the camera then select 'Record GPS Data' from the menu. All you have to do then is take your images and the GPS data will be recorded at the same time. This feature will remain active, even when the camera is switched off, so you need to manually switch this function off if you don't want it to be running at some point.
On photo upload sites and in software such as Lightroom you can drag and drop images on to a map to record where it was taken. Obviously it won't be as accurate as recording the data in-camera but it does give you a record of where the shot was roughly taken. There are also Apps available for smart phones which geotag your photos no matter what camera you use.