Méridiens

Méridiens are imaginary lines drawn on the surface of the Earth, running from the North Pole to the South Pole. They are also known as lines of longitude. Each méridien has a specific degree of longitude, ranging from 0 to 180 degrees east and 180 degrees west. The prime méridien, also known as the Greenwich méridien, is located at 0 degrees longitude and passes through Greenwich, London. All other méridiens are measured east or west of the prime méridien.

The purpose of méridiens is to help us locate positions on Earth. When combined with lines of latitude (also called parallels), they form a grid system that allows for precise geographical coordinates. This system is crucial for navigation, cartography, and various scientific applications. The distance between méridiens decreases as you move closer to the poles, converging at the North and South Poles.

Historically, the establishment of a standard prime méridien was a significant challenge. Different countries and even different scientific bodies used their own reference points. The adoption of the Greenwich méridien in the late 19th century, largely due to its association with maritime navigation and the telegraph system, provided a globally recognized standard. Time zones are also directly related to méridiens, with each time zone generally corresponding to a 15-degree longitudinal division of the Earth.