Tracking is one of the simplest, but possibly most handy, applications of GPS while hiking and backpacking. This function, available on even the least-expensive GPS units, allows you to enter a start point, for example, a trail head, and the GPS will track your location as your journey progresses. The GPS unit will record track points at given times or distances. When it's time to come home, you can follow your GPS "footprints" back to the starting point. Tracking is an excellent safeguard against getting lost.
Finding your way back home is great, but if you're unsure how to get to your destination in the first place, your GPS system allows you to enter a waypoint or series of waypoints (coordinates of notable points along your journey), then navigate to each one. As you hike toward each waypoint, the GPS unit will provide a bearing and distance. One caveat: Routing works as a bird's eye, point-to-point system, whereas you'll be traveling along a trail that isn't a straight line. Still, routing will help keep you on course and indicate if you've strayed off course. And mapping GPS units can display built-in topographic maps to make navigating the wilderness even clearer.
Geocaching is a popular outdoor sport based on GPS technology. It's basically a treasure hunt using GPS to guide seekers to the treasure. Geocaches are not quite as valuable as the treasures of story books, but they are a lot of fun to find. Often, just a weatherproof bag or container with a logbook that finders sign, geocaches are located all over the world; you can download the coordinates for them online. You navigate to the general location of the geocache using a GPS unit, then use your own intuition and detective skills to uncover it's specific location. New geocaches are constantly being added, so it's an ongoing game of hide-and-seek that can provide an entertaining hobby.
Most GPS units feature receivers only, which get your coordinates from the GPS satellite system and display them onscreen. However, certain advanced units, such as the Garmin Rino 530 HCx, include a radio transceiver, capable of broadcasting your coordinates to other compatible units. These units are excellent for large parties on backcountry trips. You can keep tabs on other members of your party and ensure that no one is left behind. Similarly, GPS tracking collars are available for dogs, helping you keep tabs on your best friend.
A number of rescue products, including Personal Locator Beacons and the SPOT Satellite Messenger, allow you to transmit your coordinates via satellite if you require professional rescue. These are basically last-resort devices designed for people faced with life-threatening circumstances. Given the lack of cell phone coverage as well as potential distances and isolation of wilderness locations, these types of devices can serve as vital survival tools for wilderness travelers. Various devices have different infrastructures in place, and not every one uses GPS, but they each offer a means of communicating with rescue teams. GPS coordinates are one way of sending an accurate location. While PLBs are strictly for emergency rescue, devices such as SPOT include additional functions that allow you to communicate in other circumstances to let your contacts know that you're OK and allow them to track your progress or to get help from personal contacts for a problematic, but non-emergency, situation such as car failure.