What defines a meridian on a map?

A meridian on a map is defined as an arc drawn between the North and South poles. This line represents a line of longitude, which is essential for locating geographical positions on Earth. Meridians are perpendicular to the equator and run from pole to pole, connecting points of equal longitude. Each meridian is defined by an angular measurement, with the prime meridian at 0 degrees longitude serving as the reference point.

The concept of a meridian is fundamental to the grid system used in mapping and navigation, where the position of any point on Earth's surface can be described using both latitude (which runs parallel to the equator) and longitude (which consists of meridians). Understanding meridians is critical for various applications in civil engineering, such as land surveying, mapping, and GPS technology.