ocr: North Pole Longitude lines are made by circles that intersect with both the North and the South Pole. Each longitude can be thought ofa as dividing the Earth in half. Longitudes are measured in half circles of0°to1 180° East and from 0° to180° West from the Royal Greenwich Observatory in - Greenwich, England. The Royal Greenwich Observatory was established in 1675 toa advance the art of South Pole navigation.
