3 ms·

> Wouldn't that make the arc-minute the practical unit? Yes. However, the earth is not a perfect sphere. The nautical mile is an average arc-minute.

• cygx 14y ago
  And the kilometer is an average centigrad.
  • ISL 14y ago
    Thanks for triggering a rarely used synapse. http://en.wikipedia.org/wiki/Grad_(angle) http://en.wikipedia.org/wiki/Grad_(angle)
• siscia 14y ago
  For what I know the nautical mile change due to your position in the Earth...