Geomagnetic field
Geomagnetic field lines are rarely horizontal and rarely aligned perfectly N-S
Angle between horizontal plane & magnetic field line = inclination
- Inclination is ~ 0° at equator & ~ 90° at poles
Angle between direction toward true north and magnetic field line = declination
- Declinations vary from point to point on earth at any one time, & vary from time to time at any one point on earth
Intensity, magnitude, or strength of field varies with position on earth and with time
- Strength is greatest at poles & weakest at equator