1. The imaginary lines drawn vertically connecting the North Pole and the South Pole are called lines or meridians of longitude.
2. These lines of longitude are seen as semi circles.
3. The 09 line of longitude is called the Prime Meridian.
4. There are 180 lines of longitude towards the East and West from the Prime Meridian.
5. So there are totally 360 lines of longitude.
6. These lines converge at the poles. The 180°W and 180°E line of longitude are the same line.
7. The lines of longitude that are found between the Prime Meridian and the 180° East line of longitude are called Eastern Longitudes.
8. The lines of longitude that are found between the Prime Meridian (0°) and the 180° West line of longitude are called Western Longitudes.
9. The part of the Earth between the 0° line of longitude and the 180° East line of longitude is known as the Eastern Hemisphere.
10. The part of the Earth from 09 line of longitude to 180° West line of longitude is called Western Hemisphere.
