( iii) Horizontal Component of Earth’ s Magnetic Field( H) If B is the intensity of earth’ s magnetic field then horizontal component of earth’ s magnetic field H = B cos δ
It acts from south to north direction. Vertical component of earth’ s magnetic field V = B sin δ
∴ B = √H 2 +
V 2 and tan δ = V / H
Angle of dip is zero at magnetic equator and 90 ° at poles. Magnetic Meridian A vertical plane passing through the magnetic axis is called magnetic median. Geographic Meridian A vertical plane passing through the geographic axis is called geographic meridian. Magnetic Map
Magnetic map is obtained by drawing lines on the surface of earth. which passes through different places having same magnetic elements.
The main lines drawn on earth’ s surface are g1 en below
( i) Isogonic Line A line joining places of equal declination is called on isogonic line.
( ii) Agonic Line A line joining places of zero declination is called an agonic line
( iii) Isoclinic Line A line joining places of equal inclination or dip is called an aclinic line,
( iv) Aclinic Line A hne joining places of zero inclination or dip is called an aclinic line.