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Latitude is North - South with 0° at the equator, 90.0° at the North pole and -90.0° at the South pole. Greenwich is approximately 51° North.
Longitude is East - West with 0° at the Observatory in Greenwich Park. Moving to the East is increasing latitude. Moving 360° East will return you to Greenwich. Moving West is decreasing latitude, negative numbers are used. Central London is slightly West of Greenwich at approximately -0.1°.
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