Meridians are lines of what type of measurement?

Meridians are lines of longitude, which are used to measure distances east or west of the Prime Meridian. The Prime Meridian is designated at 0 degrees longitude and extends from the North Pole to the South Pole. Longitude lines run vertically on the globe and are essential for navigation, mapping, and understanding time zones, as they represent how far a location is from the Prime Meridian.

In contrast, latitude lines, which run horizontally, measure distances north or south of the Equator. Altitude refers to the height of an object above a reference point, typically sea level, and depth measures how far below a point is relative to a surface, like the sea surface. These concepts, while important in geography and earth science, are distinct from the measurement associated with meridians.