Geography
Geographic Coordinates (Latitude and Longitude)
Quick fact
The system of latitude and longitude was first systematically described by the ancient Greek scholar Eratosthenes over 2,200 years ago, and the Prime Meridian was established by international agreement in 1884.
Why this is interesting
Have you ever wondered how a smartphone knows exactly where you are on Earth?
Read the full explanation
Understanding Geographic Coordinates (Latitude and Longitude)
Imagine Earth as a giant orange. To find any point on its surface, we need a grid. Latitude lines run horizontally, parallel to the equator, and measure how far north or south you are (from 0° at the equator to 90° at the poles). Longitude lines run vertically from pole to pole and measure how far east or west you are from the Prime Meridian (0°). Where a latitude and longitude line cross gives a unique address, like a street intersection. This works because Earth is nearly spherical, so angles measured from its center create precise locations.
A deeper explanation
Geographic coordinates rely on angular measurements from Earth's center. Latitude is the angle between the equator and a point north or south (measured along a meridian). Longitude is the angle between the Prime Meridian and a point east or west (measured along the equator). Together, they form a global reference system. This matters because it allows consistent, universal location sharing. Every GPS satellite broadcasts its position based on this system. Without it, modern navigation, aviation, shipping, and even ride-sharing apps would be impossible. The system is simple yet powerful, linking abstract angles to real-world places.