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GPS Navigation in the Wilds: Getting Started

Experts from Magellan offer tips on how to get started using a handheld GPS device in the outdoors
By Peter Potterfield - June 16th, 2011

Our route ascends slickrock slabs and crosses sandy washes as it winds between the fantastic red-rock formations of Arches National Park.  Nearing the end of a 20-mile day, one in which we've visited most of the highlights of the park, evening approaches. A final big loop from  the trail's end at  Double O Arch should bring us back to intersect the main trail near impressive Landscape Arch. I'm thinking we ought to arrive back on the main trail pretty soon, when I realize the Magellan eXplorist 310 GPS device in my hand can eliminate any guesswork.

The 310 gives me not just my precise position on the surface of the Earth, but pinpoints my location on a built in topo map. Looking at the colorful display I can zoom out to see the entire park (or even the entire state)  or zoom in to see where my present route will join up with the main trail--in this case, precisely 300 yards away. The device shows a "breadcrumb" trail of my entire route, overlaid on the full color map, with topo lines, roads, trails, and elevation included. As a backcountry traveler who has relied primarily on map and compass to navigate through wilderness, I'm seeing how the hand held GPS unit can add interest, useful information and precision to backcountry routefinding.

I'm lucky in that Eric Waters and Jeff Caulfield from Magellan, both experts in GPS systems and navigation, have come along on the hike to introduce the latest outdoor handheld device from the company, trade-marked named the eXplorist 310. An entry level GPS device, it's perfect for my purpose: to illustrate the basics of GPS navigation in the wilds. While lacking some of the fancy bells and whistles of other Magellan units, the 310  performs navigation tasks just as well but is less complicated to use, so it's a good device on which to demonstrate some of the fundamental parameters of GPS navigation.

GPS, for Global Positioning System, uses a network of orbiting satellites to provide a precise position anywhere on Earth. Maintained by the United States government, and originally intended for use by the military, the network of satellites became operational in the 1980s. An intentional error was built in to the system to deny accuracy to U.S adversaries, but that error was removed in 2000, allowing commercial GPS receivers to offer unprecedented position accuracy--and giving birth to the sport of  "geo-caching," which demands precision positions.

Hand-Held GPS Devices in the Outdoors

While the principles are the same, using a GPS device in the wilderness is different than using  one in the car to find the way to the dentist. Elevation and terrain matter when you're hiking, and since you are outdoors, the device has to be rugged and waterproof.  The eXplorist 310 fits the bill on all counts, and its vibrant color screen is easily readable even in direct sunlight. A carabiner clip  makes it easy to attach to a pack, or it can be used hanging from your neck with a lanyard. The SiRFstarIII chipset means the accuracy is within 10-15 feet, making it much more useful than the GPS app on your smart phone. The relative simplicity of the unit means one set of  AA batteries can keep you going for about 18 continuous hours.

The menu-driven functionality of the 310 requires only four buttons and a joy-stick selector. The unit comes with Magellan's World Edition Map, but for wilderness travel you'll want greater detail. The 310 therefore allows  downloads of Magellan's Summit Series topo maps (by U.S region, and even international locations). The more detailed downloaded maps permit the user to see topographical information rendered in color on the screen. For the hiking I wanted to do in Arches National Park, I had only to visit the Magellan GPS site, purchase and download the Rocky Mountain Region Summit Series map, and I was ready to go.

But it pays to have a couple of experts along. Before we got started, Magellan's Eric Waters and Jeff Caulfield offered some basic suggestions to make using the device more intuitive. Most commercially available GPS hand held units are default set to "North Up," which means that, much like a map, north is always up on the unit's navigation screen. But if you're traveling south, that means the arrow on the screen will point down, or behind you, which is a distracting annoyance. That, Eric tells me, can be remedied. By going to the main  menu, then to settings, I'm able to choose the "Course Up" option so that the direction of travel is always at the top of the screen. It's one of the easy changes that can make navigating with GPS more fun.

With the map loaded, and "Course Up" selected, we're ready to go. The unit starts an "active track" as soon as it's turned on, so to begin our first hike--out to stunning Delicate Arch--all we have to do is  hit the back button, go to the main menu, go to tracks, cancel the active track and start a new one. A robust unit like the eXplorist 310 can be used in multiple ways for backcountry travel. It can track your travel from the car, leaving a retraceable "breadcrumb trail" on the map, or you can choose a destination and select the "go to" feature to navigate to the desired end point. Today, we'll do both. First, I'll want to mark the location of the car. I simply go to the menu, select "waypoints,"  mark the location at the trailhead with the push of a button, and name it "Delicate Arch Trailhead."

Our first hike in Arches is out to Delicate Arch, perhaps the signature geographic location in  the state of Utah, a sandstone arch of ineffable beauty (you've seen it on the license plates). We've already loaded the Summit Series maps, which includes not just topography, roads and trails, but also "points of interest." Since Delicate Arch is most definitely a point of interest, with Eric's tutelage I go to the main menu, select POI (for points of interest), and choose Delicate Arch.  Selecting the arch as my destination puts the unit into automatic "go to" mode.  The eXplorist 310 immediately shows me an arrow that will lead me from the car in the direction I should travel to reach Delicate Arch. Not surprisingly, the arrow points me down the trail. I can zoom in for greater topographical detail, or zoom out for a broader perspective on our route. If the arrow is green, I'm headed directly for my destination; yellow and red arrows indicate I'm moving sideways or even away from my destination.

As Eric, Jeff and I follow the route across sandy desert, up slickrock ramps, and eventually up toward  the 5,000 foot plateau where the arch is situated, the unit gives me constant updates on our speed (two miles per hour) and progress toward our goal. Navigating on a sunny day from the trailhead to Delicate Arch is not a challenge, but ponder a situation where  we might be hiking through open country, with no landmarks and no rangers, trying to navigate to a known point in bad weather. The eXplorist 310 would make such backcountry travel much easier; all we'd have to do is what we're doing today, which is follow the arrow in the direction of travel, taking care not to stumble over obstacles or walk off a cliff. But as good as the Summit Series maps are in conjunction with the GPS information, it's definitely advisable to carry a good topo map along with the device. Today we use the National Geographic Trails Illustrated map for Arches National Park. (A useful tool when using a map is the Brooks Range All-In-One Map Tool Pro, which makes finding UTM coordinates, figuring distances by map, and computing bearings much easier.)

I'm a big believer that, when in the backcountry, the focus of one's attention should be on the scenery, what's out there, that's the whole reason to go. But the GPS device is not necessarily a distraction. Our exercise today demonstrates that for a mere 8 ounces, the eXplorist 310 can provide useful information, greatly assist in routefinding, and prove a potential lifesaver in white-out conditions or other trying circumstances. In conjunction with a quality map,  there is no question about location and direction of travel.

The Breadcrumb Trail and Geocaching

The other way to use a device like the eXplorist 310 is to strike out across the landscape, with no known destination, letting the GPS receiver imprint a breadcrumb trail on its internal map. With a waypoint taken at the trailhead, that strategy ensures that you can always retrace your steps to the car, or navigate cross country if necessary to the known trailhead location. To illustrate that technique, when Eric and Jeff and I arrived at the trailhead leading to Double O Arch, the longest trail in Arches National Park, we again marked a waypoint at the car, but did not enter a destination. The unit tracked our seven mile loop out to Double O Arch itself, where the trail ended, and then our backcountry loop back to rejoin the trail at Landscape Arch. I could follow our progress during the hike by checking our locations in relation to the trails imbedded in the topo map, and known points of interest. The arrow on the screen is blue when the active track has no predetermined destination.

There's little question about the utility of GPS hand held devices like the eXplorist 310. In certain situations, where routefinding is difficult, it's almost irresponsible not to take one. In fact, the more you use a good one, the more you rely on it. And its applications don't end when you return from the hike.

Once back at the car after each hike, I simply go to the main menu, save the "active track," name it appropriately, and I've captured all the data collected--our speed, our route, our elevation, and time. An added twist to navigating with a device like the eXplorist is that you can archive your backcountry travel. Simply download the free software called VantagePoint from the Magellan GPS site, and the stored data--in .gpx files--can be displayed in multiple ways. With a few clicks, VantagePoint can retreive the information, allowing you to review the route, the time it took, the places you visited, and even fly over the hike using the Summit Series map data from your unit.

Another rapidly growing use of GPS devices is the sport of geocaching, where one enthusiast places an item--as big as an ammo box or as small as a thimble--in a hidden location. The position is posted on popular websites, and treasure-hunting followers so inclined can seek out the prize. Success means you can claim having found the item on the geocache websites, failure means the dreaded DNF (did not find) notation. GreatOutdoors.com will work with Magellan to publish more about geocaching, the merits of UTM grids vs. latitude and longitude,  and other more advanced uses of GPS devices at a later date.

Map Datums

Now for the fine print. If you use the Magellan eXplorist 310 and one of the Summit Series maps, you can find your way around the backcountry with ease. If you're careful, you'll take a good topo map along with you, as a reference with greater detail, and a check against the data contained on the downloaded map. But, if you combine the two--if you take a position off the map, any map, using either latitude and longitude or the UTM grid, you have to pay attention to map datums.

A map datum is simply the elliptical model of the earth used to create the map. You don't need to know much about that, but if you transfer data, such as a position,  from a map to your GPS device, you need to know which map datum your map is based on. Most GPS devices are default set to map datum WGS 1984, but most paper maps today are based on map datum NAD27. Using a position derived from a NAD27  map on a device set for WGS 1984 is going to result in an error of  about 200 meters. That's not a big deal if you're looking for a mountain, but it could be if you're looking for a food cache. So if you are working off a paper map, you may have to select in your GPS device the correct map datum. And if you travel internationally, you will need to find the map datum used and select it from the menu in your device.

Choosing the Right Device

 If you're thinking about getting into GPS navigation, the first step is deciding on which device is right for your needs. The basic question is whether to go simple, or go for lots of features. Magellan's extensive line of hand held outdoor GPS receivers reflects the breadth of what is available in the industry. While the eXplorist 310 is a basic unit, other receivers in the line add features and complexities. Some units come with built in cameras and even video cameras. While the 310 makes way points, the eXplorist 710 can make "media points,"  marking a position with an image or even video with the GPS information imbedded. Some units, such as the 610, come preloaded with Summit Series maps, and both have internal digital compasses, voice recording capability, and touch screens, which  make naming waypoints easier. The higher end outdoor units can be used in the car with purpose-built mounts, which helps justify the extra expense. But for backcountry use, it comes down to what you need, what the power usage is, and what it's going to cost you in ounces carried.


Comments

GPS Navigation a must have!

Great informative post. I would never go backpacking in the wilderness without a really good GPS and a cell phone.

Posted on June 7, 2012 - 12:45pm
by campingandhikingoutletblog.com

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