Knowing the earth is round doesn’t mean you automatically consider a geodesic the most logical kind of ‘straight line’. Mercator exists because it’s easy to na

Knowing the earth is round doesn’t mean you automatically consider a geodesic the most logical kind of ‘straight line’. Mercator exists because it’s easy to navigate with. It’s easy to navigate with because it preserves bearings. Lines of constant bearing are, when you’re navigating on the ground, much more meaningfully ‘straight’ than geodesics. ‘Keep heading North West’ sounds like a pretty straight line.