Magnetic Declination

Définition

Magnetic declination, also known as magnetic variation, is the angle between magnetic north and true north at a particular location. This angle can vary depending on the location and changes over time due to various factors. It is an important consideration for navigation and mapping, as it can affect the accuracy of compass readings and other navigational tools.

Causes of Magnetic Declination:

  • Earth's magnetic field is not aligned perfectly with its rotational axis, causing magnetic north to be offset from true north.
  • Changes in the Earth's magnetic field over time can cause magnetic declination to vary at a particular location.
  • Local variations in the Earth's magnetic field due to geological features, such as mountains or mineral deposits, can also affect magnetic declination.

Effects of Magnetic Declination:

  • Inaccurate navigation: Magnetic declination can cause compass readings to be off by a significant amount, leading to incorrect navigation.
  • Errors in mapping: Magnetic declination can affect the accuracy of maps, as they are typically based on magnetic north.
  • Disrupting electronic devices: Magnetic declination can cause interference with electronic devices that rely on magnetic sensors, such as some types of smartphones and GPS devices.