3. ADVANCED Skill: Triangulate with two lines.
If you are traveling along a known linear feature—like a river, mapped trail, ridgeline, or road—you can skip a step when triangulating your location.
Shoot two bearings, translate them to your map, and use the known feature as your third point of reference. Your location is where the two bearings intersect the linear feature.
Adjust for Declination Navigate accurately over distances.
Maps are oriented to true north, but compasses point to magnetic north. The discrepancy is called magnetic declination, and the farther east or west you get from the 0-degree
line, the greater the impact on navigation. If you don’t correct for it (many hikers don’t), a 10-degree offset, like the one affecting parts of Colorado and Pennsylvania,
could equate to a 1.7-mile error over 10 miles of off-trail hiking. Calculate your area’s declination with NOAA’s National Geophysical Data Center
or by referencing your map’s declination diagram (in the margin). Then correct for it:
>> Automatic Set your compass’s adjustable declination and program your GPS to display true north bearings. >> Manual Shoot bearings with a non-adjusted compass. Add (for east) or subtract (for west) your area’s declination before translating the bearings to a map.
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