10.3 How does outer-core convection generate the magnetic field?
Fig 10.11a
The lines of magnetic force are very like a bar magnet. Comparing (a) to (b) note the curvature related to the angle of inclination is related to the fact that the field arises from deep inside Earth.
Fig 10.11b
Declination - the horizontal angle between the magnetic and geographic north poles.
Inclination - the vertical angle between the force field line and Earth's surface.