How to Use a Altimeter

If you're lost and wandering in the mountain wilderness, you'll be thankful you have an altimeter in your pack. Used with a good topographic map, this handy gauge can make the difference between quickly finding your trail again or spending some time---perhaps hours or days---not knowing exactly where you are. An altimeter measures your elevation above sea level. The instrument is small, light, and easy to use; some versions are built directly into a watch, allowing you the use of an altimeter without adding a separate piece of equipment.

Things You'll Need

  • Map
  • Compass
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Instructions

    • 1

      Ensure the device is operating. Most altimeters are constantly "on," because powering off would require recalibration. Altimeters use air pressure and operator settings to determine your elevation above sea level. Air pressure decreases at a predictable rate as your elevation rises.

    • 2

      Cycle to the altimeter setting if your device offers multiple settings. The device gives elevation according to the last calibration that the operator performed. Remember that air pressure or barometric pressure can change, and you will have to compensate for that change in order to use the device.

    • 3

      Reset the altimeter at a place of known elevation. Topographic maps can assist you by indicating the elevation at important landmarks. Trailheads often have signs indicating elevation. Match the altimeter reading with the known elevation. There will be a keypad or up/down buttons to change the reading. Alternatively, you can reset the altimeter if you know the barometric pressure from a device or current weather report for your location.

    • 4

      Continue to reset the altimeter whenever you reach a point where elevation is indicated, either on the map or by a reliable sign. Although it seems bothersome, resetting your altimeter can be crucial if you become lost.

    • 5

      Check the altimeter reading if you become lost. Use the elevation markings on your map; finding a marking that corresponds to your altimeter reading will help you determine your position. Use a compass on the map to indicate the direction to the nearest trail or to a landmark on the map.