Magnetic Dip and Magnetic Declination
The vertical angle between magnetic needle and earth surface is called angle of dip.
Magnetic Dip at equator is 0 degree.
Magnetic Dip at pole is 90 degree.
Dip is positive if needle points towards the ground.
Dip is negative if needle points away from the ground.
The horizontal angle between magnetic meridian and true meridian is called declination.
Magnetic declination is positive towards east direction.
Magnetic declination is negative towards west direction.
The line connecting points with same magnetic declination is called isogonic line.
The isogonic line with 0 magnetic declination is called isoclinic line.