>Whoa, wait a second...is this saying that roads which look straight on a map are actually not straight, in the sense that they're not actually following the sh

>Whoa, wait a second...is this saying that roads which look straight on a map are actually not straight, in the sense that they're not actually following the shortest path between two points? The Gaussian curvature of Earth is small enough that for distances below 50 miles and locations south of the Arctic Circle, it really doesn't matter. But the nice thing about the Mercator map is that it shows a constant bearing (Δlat/Δlong) as a straight line. The only projection which shows great circles as straight lines is the gnomonic projection, but this is limited to showing a very small region before distortion becomes unacceptable.