Difference Between True North And Magnetic North
As we set our direction when navigating, it is important to understand the difference between true north and magnetic north. True north is the geographic north pole, while magnetic north is the angle of the Earth’s magnetic field. This article will expand on how these two elements differ in regards to navigating and how they can be used to find our way.
How True North and Magnetic North Differ
True north is based on the geographic north pole, which is the northernmost point on the planet. This is a fixed point in the Earth’s rotational axis, and is the point used to measure around the globe. This is what we typically think of when talking about directions on the globe, and is often used in modern navigation.
Magnetic north is different as it is not a fixed point, and instead is affected by the Earth’s magnetic field. This means that the angle of the magnetic field relative to true north can be different depending on location. In some areas, the angle between true north and magnetic north can differ by thousands of miles and can move over time.
How Magnetic North Affects Navigational Instruments
Navigational instruments are designed to determine direction based on the angle of the magnetic north. This is different than true north, as these instruments measure the angle between the magnetic field and the direction being traveled. This means that devices such as compasses and GPS systems need to be calibrated correctly in order to accurately determine direction.
It is important to note that this calibration has to be done on a regular basis, as the angle between true north and magnetic north can change over time. This is due to the movement of the Earth’s magnetic field, so it is important to double-check the accuracy of navigational instruments before setting off on an adventure.
True North vs Magnetic North on Maps
When looking at maps, it can be easy to confuse the two norths. On most maps, the orientation of north will usually be indicated by the top of the map, however this does not necessarily mean that this is true north. A closer look at the map will usually show an arrow indicating the angle of magnetic north, enabling viewers to distinguish between the two.
When it is difficult to find an arrow marking the magnetic north on a paper map, the legend (key) will usually contain an indication of true north and magnetic north. This is helpful, as it allows for easy reference to orient oneself correctly when traveling.
How To Calculate True North
When using a navigational compass, it often requires that users calculate the angle between true north and magnetic north. This can be done by taking the bearing of the compass (the direction it is pointing in) and subtracting the value of magnetic declination from it. This will give the bearing relative to true north, and can be used to ensure more accurate navigation.
In addition to this, the angle of declination can also be found in maps as an angle line. This angle line will represent the difference between true north and magnetic north, and is a useful reference when calculating direction.
The Impact of Altitude on Magnetic North
The position of magnetic north can also be affected by altitude. For example, if you are situated at a high altitude, the angle of the magnetic field relative to true north will be different. This is why, when navigating, it is important to take into account the altitude of your location.
This is especially the case when the distance between true north and magnetic north is greater. This difference can be more pronounced when navigating through areas with different altitudes, so it is important to accurately calculate the difference when orienting oneself.
Using True North and Magnetic North for Navigation
When navigating, it is important to understand the difference between true north and magnetic north. This understanding can be used to ensure more accurate navigational results, as it will enable users to take the angle of the magnetic field into account when determining an accurate bearing. It is also important to understand how the difference between the Two Norths can be impacted by altitude.
It is also helpful to understand how to calculate the bearing relative to true north. This is done by calculating the angle of declination between true north and magnetic north, as well as taking into account any changes in altitude. By understanding how these two points of reference differ, navigators can more accurately determine direction and travel safely.
Summary
True north and magnetic north are two essential points of navigation that are important to understand. True north is based on the geographic north pole, while magnetic north is affected by the Earth’s magnetic field. Navigational instruments, such as compasses, must be regularly calibrated in order to take into account the angle of the magnetic field. Additionally, altitude can also affect the difference between true north and magnetic north. By understanding the difference between these two points of reference, navigators can more accurately determine direction and reach their desired destination safely.
