Navigation: What About GPS?

by Phil Romig Jr


GPS has been all the rage for the last few years. It has become so popular that some people discuss it without knowing what the acronym means (Global Positioning System) or how it works. Occasionally, the marketing hype reminds me of cable-TV companies who try to convince us that we will be woefully uninformed without access to a few million channels or the cell phone ads that tell us our very existence is threatened if we don’t post online videos of ourselves brushing our teeth every night.


There are stories about people who have been in serious trouble because they relied solely on a GPS when they left the paved highway. As the 2011 Pack Llama Festival was happening in Silverton, CO, there were several newspaper stories of “Death by GPS” that included:

  • A mother and her 11-year-old son were stranded after following a GPS into Death Valley; her son died.
  • In northern Nevada, a husband and wife became stuck while following a shortcut shown on their GPS; the husband died.
    In Spain, two men were so focused on following a route on their GPS that they didn’t notice a reservoir till they drove into it; one of the men died.

The common thread in these cases is that the people involved did not plan ahead and did not tell anyone where they were going; they had no map, compass, emergency communication device, food or water; and they put all of their faith in a GPS that they did not know how to use properly.


Even if you are able to stay out of serious trouble, there are other pitfalls of GPS. For example, suppose that a close friend tells you about a backcountry fishing hot spot on the condition that you keep it secret. On your first trip, you catch a huge trout and take a picture of it with your cell phone. After you get home, you proudly post the picture on your Facebook page, only to discover (too late) that the coordinates of the lake (calculated by your cell phone’s GPS) are part of the posting.


People have been hiking the backcountry for a long time without getting lost, so it’s reasonable to ask: What is GPS, what can it do for you, and, considering all the pitfalls and hazards, why should you care?


How does GPS work?
Imagine that you bury a coffee can full of money in the yard and you want your grandchildren to dig it up after you’re gone. Before you fill the hole, you measure the distance to three reference points—a corner of the house, a fireplug and the water meter—and put the measurements in a sealed envelope. Years later, your grandchildren are given the envelope, and they open it and find the measurements. They cut three strings to the exact lengths listed and fasten one end of each string to the appropriate reference point. They pull the three cords tight, dig where the ends meet, and find the treasure.


GPS works the same way. The “reference points” are satellites in orbit around the earth, and the length of each “string” is the time it takes a radio signal to travel from a satellite to a GPS receiver. The receiver uses those lengths to calculate geographic coordinates that let you plot its location on a map.


My first GPS receiver, the Magellen GPS Trailblazer, calculated its location and not much else. Modern GPS receivers are navigation computers that can display maps and satellite photos, point out the direction of the next leg of your route, tell you how far it is and how long it will take to get to your destination, double as a compass, barometer or camera, and much more.


Today, almost anything you want to do with GPS is available, but that begs the question of whether you need that capability. The first rule of backcountry GPS is: “Anyone who needs a GPS should not be allowed to have one.” There are many reasons why a GPS receiver can fail: batteries can burn out, a computer chip can die, and environmental conditions can make it unreliable (to name just a few). If a person can’t navigate with a map and compass, they should not be in the backcountry. They put their lives at risk if they depend solely on GPS.


What can GPS do for you?
Using GPS along with a map, compass and dead reckoning can help you be more confident and relaxed, make it easier to deviate from your original route or find hidden targets, and show you the way in fog or snow. Some units can assure family and friends that you are okay and can summon help in an emergency. On trails that you have used for years, a GPS receiver enables you to plot a trip on a map, create an elevation profile, and add geo-tagged photographs and a diary to produce an enjoyable, attractive record of the trip that you and your companions will remember for years.


Once you have a GPS receiver, you begin to discover other uses for it. A few years ago, my fishing buddy, Lennie, bought some land in the mountains where he dreamed of building a cabin. True to form, he couldn’t find the corner stakes, so he didn’t know exactly where the property’s boundaries were. Last weekend, using my backcountry GPS receiver, we found the corners and mapped the boundaries in a couple of hours. The next day we used the same GPS unit, this time mounted on the dashboard of Lennie’s truck, to find our way around Denver.


GPS offers so many benefits and, with the advent of smart phones, is so ubiquitous that everyone should take it seriously and learn more about it. It is not simple: for example, to plot a GPS position on a map, both must be using the same map datum and coordinate system. However, almost everyone who learns how to use a GPS receiver effectively concludes that it is well worth the effort.


How do you get started?
Winter is the perfect time to learn to use a new GPS unit, which makes a GPS unit an excellent holiday gift. Fortunately, this issue of The Backcountry Llama arrived in time for you to add a GPS to your wish list.