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Lines of latitude and longitude are used to locate places accurately on the Earth's surface.

Latitude

Lines of latitude circle the Earth in an east-west direction. They are parallel.

They are different lengths, eg:

• the equator is 40,075 km long
• the Antarctic circle is 17,662 km long
• the South Pole is 0 km long

Important lines of latitude:

• the equator (0°)
• the Tropic of Cancer (23.5° north)
• the Tropic of Capricorn (23.5° south)
• the Arctic circle (66.5° north)
• the Antarctic circle (66.5° south)
• the North Pole (90° north)
• the South Pole (90° south)

Longitude

Lines of longitude run from the top of the Earth to the bottom. They are not parallel as lines of latitude are - they meet at a point at the north and south poles and are called meridians.

They divide the Earth into segments, like an orange. Some important details about these lines include:

• The line which runs through Greenwich in London is called the Greenwich Meridian or Prime Meridian. The Prime Meridian is 0° longitude.
• The Earth is then divided into 180° east and 180° west.
• The International Date Line lies at 180° east/west.

The index of an atlas gives shows where places can be found, eg Birmingham, UK - 52° north 1° west. This means that Birmingham is located at approximately latitude 52 north and longitude 1 west.