What describes the role of meridians in navigation?

Meridians serve an essential role in navigation by measuring angular distance east and west from the Prime Meridian, which is designated as 0 degrees longitude. This measurement is crucial for pinpointing a specific location on the Earth’s surface, allowing navigators to determine their longitude, as meridians run vertically from pole to pole. They enable the establishment of a coordinate system in conjunction with parallels, which measure latitude.

The concept of meridians is central to navigation because they provide a framework for mapping and charting routes, particularly for maritime and aerial navigation. Understanding a vessel’s or aircraft's position relative to these meridians is vital for accurate navigation and course plotting. Thus, distinguishing between the roles of meridians and parallels is key, as meridians focus on longitudinal measurements, while parallels deal with latitudinal measurements, which help determine distances north and south of the equator.