Geographic Coordinates and Distance

Every point on the Earth's surface is determined by its geographic latitude and longitude.

Coordinates

• Latitude: north/south of the equator, 0°-90° (N or S).
• Longitude: east/west of Greenwich, 0°-180° (E or W).
• Parallels are circles parallel to the equator. Meridians are semicircles connecting the poles.
• The tropics lie at latitude 23.5°, the polar circles at 66.5°. The Northern Tropic (Tropic of Cancer) passes at 23.5° N, the Southern Tropic at 23.5° S.
• Tashkent is at approximately 41° N, 69° E.

Line	Latitude
Equator	0°
Tropics	23,5°
Polar circles	66,5°
Poles	90°

Distance

• The arc of 1° of a meridian is approximately 111 km.
• Distance along one meridian = latitude difference × 111 km.
• For example: between 41° N and 44° N it is 3° × 111 = 333 km.
• 1° = 60′, 1′ is approximately 1.85 km.
• The length of the equator is approximately 40 000 km.
• Along a parallel, 1° becomes shorter toward the pole. It is longest at the equator and equal to zero at the pole.

1. Write down the latitudes of the two points
2. Find the difference
3. Multiply by 111 km