What is geographic Meridian?
Thereof, what is geographic meridian and magnetic meridian?
The axis line for the geographical true north/south is called the geographical meridian and the axis line joining the magnetic north/south is called the magnetic meridian. The North Magnetic Pole moves over time due to magnetic changes in the Earth's core.
One may also ask, what is the use of Meridian?
Meridian, imaginary north–south line on the Earth's surface that connects both geographic poles; it is used to indicate longitude.
In geography, longitude is the distance on the earth's surface, east or west of a defined meridian, usually the meridian of Greenwich, England (0° Longitude), expressed in angular measurements from 180° West (or -180°) to 180° East. Latitude and longitude can be used together to specify a precise location on the Earth.