Conversely, if your local noon occurs after GMT, you are West.
We apply similar coordinate systems to map the surfaces of Mars and the Moon. meridian longitude
Meridian longitude is a fundamental concept in geographic coordinate systems. It refers to the angular distance, measured in degrees, east or west of a prime meridian. Longitude lines (meridians) run from the North Pole to the South Pole and are essential for navigation, timekeeping, and mapping. Conversely, if your local noon occurs after GMT,
While the "Reference Meridian" used by modern GPS (the IERS Reference Meridian) actually sits about 100 meters east of the historic Greenwich observatory due to more precise satellite measurements, the principle remains the same. Whether you are tagging a photo on social media, navigating a commercial airliner, or tracking a shipping container across the ocean, you are utilizing the invisible grid of meridian longitude. It refers to the angular distance, measured in
