Aha, that makes perfect sense. It's not suggesting that the underlying property is only true of the Mercator projection, but that people are most likely to be c

Aha, that makes perfect sense. It's not suggesting that the underlying property is only true of the Mercator projection, but that people are most likely to be confused by that property when they think in terms of the Mercator projection. > because the nautical mile is (or more accurately was) defined by a minute of latitude Cool, I've heard that in the past but somehow always forget about it! You have: (arcminute/circle) earthradius * two pi You want: nauticalmile * 1.0006759 / 0.9993246 Thanks!