What are Geodesic distances?
A geodesic line is the shortest path between two points on a curved surface, like the Earth. They are the analogue of a straight line on a plane surface or whose sectioning plane at all points along the line remains normal to the surface. It is a way of showing distance on an ellipsoid whilst that distance is being projected onto a flat surface.
However there are several types of lines that have different definitions which are listed at the bottom of this blog.
Here's a video example of a geodesic line, the longest geodesic line possible without touching land.
