Understanding Magnetic Declination and Its Implications
When navigating the outdoors, it’s essential to have an understanding of magnetic declination. At its core, this refers to the difference between true north and magnetic north.
The Basics of Magnetic Declination
In simple terms, magnetic declination refers to the angle between true north, as indicated by the Earth’s axis, and magnetic north, as indicated by the Earth’s magnetic field. This angle is not constant and can vary based on location and time.
At some points in history, magnetic north and true north have been aligned. At other times, they have varied by as much as tens of degrees. Today, magnetic declination is an important consideration for navigators using tools like maps, compasses, and GPS devices.
Why Magnetic Declination Matters
If you’re navigating using a tool that relies on magnetism, such as a compass, ignoring magnetic declination can lead to significant errors. For example, if you’re trying to navigate using a map that doesn’t take into account magnetic declination, your measured bearing may not align with your true intended direction of travel.
Not accounting for magnetic declination can also cause confusion and danger in certain situations, such as when traveling in areas with unique magnetic properties or when dealing with topographical features that can interfere with a compass.
How to Adjust for Magnetic Declination
To account for magnetic declination when using a compass or map, you’ll need to determine the difference between true north and magnetic north for your location. There are numerous online resources and mobile apps that can help you calculate magnetic declination quickly and easily.
Once you’ve determined the difference, you’ll need to adjust your compass or map accordingly so that your measurements align with your true intended direction of travel. This involves rotating the compass housing or adjusting the orientation of the map. Most compasses and maps have adjustable features to make this process straightforward.
The Bottom Line
While it may seem like a minor detail, understanding magnetic declination plays a critical role in accurate navigation. By taking the time to account for magnetic declination and adjust your tools accordingly, you’ll ensure that you’re on the right track and minimize the risk of getting lost or encountering hazards.
