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)
 
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Important!
Prime Meridian: \(0°\) line of longitude
Number of lines on 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 \(111\) km
At \(45°\) latitude\(79\) km
Important!
As the longitudes converge there is no space between them at the poles .
Eastern Hemisphere: The portion of the Earth that lies between the \(0°\) line of longitude and the \(180° \)East line of longitude.
 
Eastern hemisphere.JPG
  
Western Hemisphere: The portion of the Earth that lies between  \(0°\) line of longitude to \(180°\)West line of longitude.
western hemisphere.jpg