Longitude — Meridian

It ranges from 0° at the Prime Meridian to 180° both eastward and westward.

Meridian longitude is more than just a line on a map; it is a mathematical triumph that synchronized the world’s clocks and opened the door to global exploration. Whether you are checking the time or ordering a package from across the globe, you are using the legacy of the meridians. meridian longitude

For centuries, different nations used their own "starting" meridians (often based in Paris, Lisbon, or Rio de Janeiro). This made international navigation a nightmare. It ranges from 0° at the Prime Meridian