# Gnomonic projection

- Author:
- Šárka Voráčová

Determine the image of Prague, Baku, Shanghai, Reykjavík and Vencouver. Draw the great circle between Prague and Shanghai.

A gnomonic map projection displays all great circles as straight lines, resulting in any straight line segment on a gnomonic map showing a geodesic, the shortest route between the segment's two endpoints. This is achieved by casting surface points of the sphere onto a tangent plane, each landing where a ray from the center of the sphere passes through the point on the surface and then on to the plane. No distortion occurs at the tangent point, but distortion increases rapidly away from it.