TAKING A BEARING WITH A COMPASS

compasses

A compass makes wilderness navigation possible by enabling you to accurately gauge directions from your current position to identifiable landmarks throughout the terrain that surrounds you.

The most basic function a compass provides is pointing north (magnetic north, that is). An orienteering-style compass allows you to assign a numeric value (a "bearing") to any direction in the 360° circle around you. This means you can head toward a specific spot rather than simply ambling "south-southwest" or "due east."

The rotating bezel of a compass is used to convert general compass directions into specific bearings. A bezel's outer edge includes index (degree) lines that breaks down the 360° circle into 2° or 5° increments.

A bezel measures the direction towards a given object in terms of an angle—specifically, the clockwise angle between a straight line pointing due north and a straight line pointing toward the object. This bezel allows you to express any specific direction as a number between 0° and 360°.

Why is it useful to know that your campsite lies on a bearing of 40° instead of "to the northeast"? Because precise navigation results in efficiency, safety and speed.

Following a bearing off by just 1° can translate into almost 100 feet of error after 1 mile. That means that after a 5-mile hike, you could miss your target by almost 500 feet. In the wilderness, a few dozen feet can mean the difference between spotting a campsite or other landmark and missing it completely.
Transferring Bearings

On most backcountry excursions, especially those planned by beginners, compass navigation is seldom necessary. Simply following the trail carefully and checking your map from time to time should get you from campsite to campsite safely.

But if you become disoriented, or are just feeling confidently adventurous, a compass becomes a splendidly useful tool.

For example, if you know your location on the map, you can take a bearing on an unseen target elsewhere on the map and head toward that destination simply by following the bearing—even though your objective is not yet visible. Check out our video for a visual demonstration of how to transfer a bearing from map to compass:

  • Identify your position and your objective on the map. Connecting those two points creates a line on the map (which you can either visualize or physically draw on the map).
  • Align the edge of your compass with that line.
  • Rotate the bezel so its orienting lines run parallel with the map's orienting lines (which point to true north). This means the actual bearing have been captured at the front of the compass.
  • Take the compass and turn your body until the magnetic needle lines up with the orienting arrow on the compass. At point, you will be facing the direction that will lead to your chosen objective.

You can rearrange the process and use a compass to take a bearing off a real-world object (one that is known to be on your map) and transfer that information to the map to identify your location even if you are uncertain of your whereabouts in the field. Our companion video illustrates these steps:

  • Hold the compass level and aim the front of it at an object.
  • Rotate the bezel until the magnetic needle is aligned with the orienting arrow of the compass.
  • Locate the object on the map and place the edge of the compass on that object.
  • With the edge still tight against the object, and without touching the dial, turn the entire compass until the orienting lines within the bezel line up with the orienting lines on the map.
  • The edge of the compass forms a line on the map, and you now know you are somewhere along that line.

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