Längengrade

Längengrade, also known as longitude, are a geographic coordinate system that specifies the east-west position of a point on the Earth's surface. They are angular measurements, expressed in degrees, minutes, and seconds, east or west of the Prime Meridian. The Prime Meridian, designated as 0 degrees longitude, passes through Greenwich, London, England.

Lines of longitude, called meridians, run from the North Pole to the South Pole. They are semicircles that converge at the poles. The Earth is divided into 360 degrees of longitude. Therefore, there are 180 degrees of longitude east of the Prime Meridian and 180 degrees of longitude west of the Prime Meridian. The International Date Line roughly follows the 180th meridian, marking the boundary between one calendar day and the next.

The distance represented by one degree of longitude varies depending on the latitude. At the equator, one degree of longitude is approximately 111.32 kilometers (69.17 miles). As one moves towards the poles, the distance decreases because the meridians converge. At the poles themselves, all lines of longitude meet, so the distance is zero.

Determining longitude historically posed a significant challenge for navigation. While latitude could be determined relatively easily using celestial observations, measuring longitude required precise timekeeping. The development of accurate marine chronometers in the 18th century was a crucial breakthrough, allowing ships to accurately calculate their position at sea. Today, global positioning systems (GPS) provide highly accurate longitude and latitude coordinates.