Simple, clear explanation of the Haversine formula used to calculate distances on Earth. No advanced math required.
The Haversine formula calculates the great-circle distance between two points on a sphere using their latitude and longitude. It is the standard method behind almost every online distance calculator, including SnapDistance.
This guide walks through what each part of the formula does, why we use a sphere (and the small accuracy trade-offs), and where the formula came from. No advanced math is required to follow it.
By the end you will understand exactly what number SnapDistance is producing when it says two cities are X kilometers apart.