The Global Positioning System (GPS) is a worldwide navigation system of about 24 satellites and their ground stations, originally developed for military use. GPS units use these satellites as reference points to calculate positions on the ground accurately within a matter of yards. GPS tools are now used in cars, boats, planes, construction equipment, movie making gear, farm machinery, and laptop computers. Our interest in them lies mostly with use in hiking and backpacking experiences, but we have great units for auto travel as well. And, we have devices that combine use of GPS satellites with communication satellites that allow backcountry travelers to stay in touch with home, and for those at home to know where the user is located. See information on renting the SPOT Messenger and renting the DeLorme InReach.


After a lot of research, we settled on a few particular GPS units we believe offer the best balance of features for backcountry use and simplicity. Handheld GPS units are neither the answer to all of your backcountry navigation problems, nor are they just another expensive trendy gadget. The reality lies somewhere in between; we'll help you sort out the hype from real help. Excellent background information on the GPS satellite system and the basics of how it works can be found on Garmin's site and other sites around the web - highly recommended to help you better understand how a GPS unit works. Better yet, someone else has already written it up for me!

There are many different styles, types and sizes of GPS units available, and all will, and won't, do certain things of importance to hikers. Watch our video on our GPS units. For example, here are a few practical things you can do with a good GPS unit while exploring the woods:

  • Pinpoint your exact location in longitude and latitude even when its dark, foggy, or you don't otherwise have the slightest idea where you are.
  • Determine the distance and direction from your location to another specified point.
  • Mark where you park your car, so you always know which way to get back.
  • Establish your altitude, and track your elevation history as a profile.
  • Automatically trace a route you are hiking, so you can retrace your steps if necessary without getting lost.
  • Show what direction you need to go to get back on track.
  • Mark locations along your route, or intended route, with "waypoints" - like digital bread crumbs and flag markers, if you will.
  • Offer traditional navigation assistance with a built-in digital compass, if available.

But here are a few other 'real-trail' things that GPS ads won't always tell you:

  • You must still carry a map and regular compass. GPS units don't always work the way you might expect, and you don't always have the coordinates you need for a destination, so you need a paper map for reference and a compass as backup.
  • GPS units don't work well, if at all, in buildings or under tree heavy cover. So if you're in a forest, you may need to find a clearing to set your position, which isn't always easy.
  • GPS units go thru batteries like twigs in a fire if you keep them on for extended times - which you need to do for tracing routes, for instance.
  • GPS units can be frustrating at times, like any other electronic device. But I've not thrown one up against a tree yet, since I figure it is usually operator error.
  • It's easy enough to grasp the basics of GPS units; but they are fairly difficult to master to maximize their benefits.
  • When a GPS unit indicates you are one mile from a designated spot, that is an "as the crow flies" mile, not a trail mile.
  • When a GPS unit indicates you should go due east to your designated spot, it doesn't know if there is a mountain, swamp or canyon between you and the target - another good reason you still need a paper map.

If you get a GPS unit - and I admit they are easy to get hooked on, so they are definitely recommended - the best way to figure the thing out is to play with it. At home, where you're not likely to get lost depending on it. Like a new tent, don't take it out for the first time without learning something about it at home first.

The first thing a GPS unit does when you turn it on is to start looking for satellite signals, trying to nail down its position. You may get a signal meter like on a cell phone, or it will tell you how many satellites it is communicating with - most need at least 3 or 4 to be accurate. With the very first use you may need to give it an initial "calibration", the steps to which will be in the unit's manual or "Quick Start" guide. This short, simple process is something you may need to repeat from time to time if you use it in widely varied geographic areas.

The basic GPS skills I suggest you first learn are:

1) how to set a waypoint of your current location;

2) how to enter the coordinates of a different location from a map or other reference source;

3) how to determine directions from your current location to another waypoint;

4) how to use the built in compass and altimeter;

5) how to replace the batteries.

Each is easy to learn in a few minutes of experimenting or reading the instructions. If you can do these, you're ready to make GPS useful on the trail, where you can fine-tune your understanding of how all the features function together. We also have a nice library of how-to articles on this site. If you rent a GPS, we will include a print or online user guide with full details on how to use it. We are available to assist you over the phone as needed. Links to these informational articles:

How to Mark a Waypoint with a GPS
How to Manually Enter a Waypoint Coordinate into a GPS
How to Navigate to a Waypoint with a GPS
How and Why to Change Map Orientation on a GPS
How to Change Measurement Units and Map Format Setting on a GPS
How to Record a Track of Waypoints on a GPS
How to Use a GPS to Find Your Location on a Map
What does WAAS Mean for a GPS
Using a GPS for Geocaching

To keep learning about navigating in the backcountry see our books GPS Made Easy and Wilderness Navigation.


Our Garmin eTrex unit offers basic navigation at a great rental value. Watch our video on our GPS units. We also have a dedicated page where you can rent a wide variety of auto navigation units for driving in all corners of the world.

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