Theory:
Longitudes
- Imaginary lines
- Sketched vertically connecting the North Pole and the South Pole.
- They are also called lines or meridians of longitude.
- These lines of longitude are seen as semi circles.
Degrees of longitudes can be divided into minutes and each minute of longitude can be further divided into seconds.
Important!
1° (degree) = 60' (minutes)
1' (minute) = 60'' (seconds)

Important!
Prime Meridian: \(0°\) line of longitude
Number of lines on the either side of Prime meridian:\(180\)lines of longitude
Total lines of longitude:\(360\)lines.
- These lines converge at the poles.
- The 180° W and 180° E line of longitude are the same line.
- Eastern Longitudes: The lines of longitude found between the Prime Meridian(\(0°\)) and the\( 180° \)East line of longitude.
- Western Longitudes: The lines of longitude found between the Prime Meridian (\(0°\)) and the\( 180°\)West line of longitude.
Two opposite meridians form a great circle.
The lines of longitude are
At Equator: | Semi circles covering 111km |
At 45° latitude | 79km |
Important!
As the longitudes converge there is no space between them at the poles .
Eastern Hemisphere: The portion of the Earth between the \(0°\) line of longitude and the \(180° \)East line of longitude.

Western Hemisphere: The portion of the Earth that lies between \(0°\) line of longitude to \(180°\)West line of longitude.
