Magnetic declination are the difference between True North and Magnetic North, and magnetic declination can cause a person to become lost if a person dont account for magnetic declination. True North is a fixed point that align with the rotation of the Earth, but Magnetic North is a moving target because the molten cores of the Earth shifts. Because True North and Magnetic North isnt in the same location, a compass needle will not point to an same direction that a map indicates.
If a person use a compass without adjusting for magnetic declination, the compass will provide a direction that is more different than the direction shown on a map. This difference in direction is called magnetic declination, and magnetic declination can lead to significant error in navigation over long distance. The direction of magnetic declination change based off a persons geographic location, and the direction of magnetic declination changes depending on whether a person is in the eastern or western United States.
What Is Magnetic Declination and How to Adjust Your Compass
For example, a person hiking in the Pacific Northwest will encounter an eastern declination, which mean the magnetic pull is skewed toward the east. Conversely, a person hiking in the eastern half of the United States will encounter a western declination. Because the direction of magnetic declination can be either east or west, you must know the specific direction of magnetic declination for you location.
If you apply the wrong direction of correction for magnetic declination, you will move in the wrong direction. You can use mathematical rules to adjust your compass bearing for magnetic declination, but you must apply the correct rule for the specific direction of magnetic declination. For eastern declination, you must subtract the magnetic declination value from your magnetic reading, and people often call this rule “east is least.” For western declination, you must add the magnetic declination value to your bearing.
Because performing math can be difficult when a person is tired or cold, many navigators uses a compass that has a built in adjustment bezel. A compass with a built-in adjustment bezel allow you to set the magnetic declination directly into the compass, and setting the magnetic declination into the compass ensure that the compass provide the correct direction automaticly. Magnetic declination is not a permanent value, and magnetic declination change every year because the magnetic poles shifts.
Because magnetic declination change, the magnetic declination values found on an old map may not be accurate for your current trip. You must always check for the most recent magnetic declination data before you begin a hike, and you must ensure that the magnetic declination data are current. Additionally, you must keep your compass away from metal vehicle and electronic device, because metal vehicle and electronic device can interfere with how a compass function.
Precision are necessary when a person is navigating, and precision is necessary because magnetic declination can cause a person to lose the trail. You should of checked teh data before you left.
