What defines longitude in geographical coordinates?

Longitude in geographical coordinates is defined by vertical lines that run from the North Pole to the South Pole. These vertical parallels, often referred to as meridians, indicate the east-west position of a point on the Earth's surface relative to the Prime Meridian, which is designated as 0 degrees longitude. The measurement of longitude helps determine how far a location is from the Prime Meridian in degrees, with values ranging from 0 to 180 degrees east or west.

The concept of vertical parallels is essential for navigation and mapping, as they intersect with horizontal lines of latitude, forming a grid system used to pinpoint exact locations on Earth. This system is critical for various applications, including GPS technology and geographic information systems (GIS). Understanding longitude allows for more accurate travel and better understanding of global relations between different locations.