Quick Answer
Your compass needle is not pointing north due to declination, which is the difference between magnetic north and true north. This discrepancy can be caused by the Earth's magnetic field variations and the movement of tectonic plates.
Understanding Declination
Declination is a crucial factor to consider when using a compass for navigation. It varies by location, and its value can range from 5 to 20 degrees in different parts of the world. To determine the declination for your area, consult a declination chart or a website that provides declination values for your region. In the US, for example, the declination value ranges from -20 to 20 degrees.
Calculating Magnetic North
To calculate magnetic north, add the declination value to your compass reading. For example, if your compass needle points to 360 degrees and the declination value for your area is 15 degrees, then magnetic north would be at 375 degrees. On the other hand, if you are in an area with a negative declination, subtract the value from your compass reading.
Orienting Your Map
When orienting your map, use the magnetic needle reading, not the true north direction. This ensures that your map is aligned with the magnetic north, which will guide you in the right direction. To orient your map, place the map on a flat surface and align the map’s north-south lines with the magnetic needle. Make sure to account for declination when using your compass to navigate.
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