Backpacker Magazine – August 2011

The Manual: Plan a Trip with GPS

Learn how to plot your own digital adventures with precision--then print the maps and prep your GPS.

by: Excerpted with permission from Using a GPS, by Bruce Grubbs

Tags:
• Skills
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• GPS
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Plot Your Own Route
GPS software does a lot more than enable digital transfers. Most programs also come with tools for plotting routes and adding symbols, waypoints, and text notes. You can measure distances and directions, too. Here are the key steps:

>> Craft your path (A) With digital maps, create a new route and add waypoints to it by selecting the waypoint tool and clicking on the map. Put in as many waypoints as you need to follow the twists and turns of the trail. Be sure to put a waypoint at every key spot, such as trail junctions, springs, campsites, and any other points of interest. Tip: For loop trips, place an ending waypoint next to the starting point, rather than using the same waypoint, which can confuse the GPS receiver.

>> Name waypoints and routes (B) Although the program names each waypoint automatically, applying a sequence like 001, 002, 003, etc., add a descriptive name, within the limitations of your GPS, such as “trailhead.” It’ll be easier to use the waypoints in the field.

>> Create an elevation profile (C) Most mapping programs allow you to plot a graph of your route depicting how the elevation varies with distance. Typically you do this by right-clicking the route line. Mileage is shown along the profile, which lets you see where the long climbs and steep descents are located.

Print the Map
On your trip, always carry a printout of your digital map, ideally one using the UTM (Universal Transverse Mercator) coordinate “grid” system. The grid is made up entirely of one-kilometer squares (versus the varying distances of latitude/longitude lines). This makes it easier to enter waypoints using the map (or to plot them) in the field. Also, make sure your GPS is synced with the map datum of the printed map. The most common datums are NAD27, NAD83, and WGS84. Favorite map-printing site: MyTopo.com. This service creates seamless, waterproof maps sized and centered to reduce the need to carry multiple maps. MyTopo is also synced with the trips offered at backpacker.com/hikes.

Upload to Your GPS
Once you have your trip plotted, it’s time to upload it to your GPS receiver: >> First, connect the receiver to your computer with a USB cable and turn it on. >> If you’re using software that didn’t come with your GPS unit, use its GPS setup feature to tell the mapping program your GPS brand and model, as well as the connection type. >> Use the “export to GPS” function to send the data to the GPS.

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