[Sean C]

Originally Posted by Capt Jack Harkness

Close, according to this http://www.coastalnavigation.com/sam..._pages/1_2.htm it's one arc second, not minute.

Actually, it says the opposite...which is correct.

Originally Posted by coastalnavigation.com

One minute of latitude equals one nautical mile and degrees of latitude are 60 nm apart.

Degrees of longitude are also 60nm apart at the Equator. Differences in longitude further away from the Equator can be approximated by dividing the distance in nm by the cosine of the latitude. For instance:

60nm ÷ cos(45) = 84.85

...so at 45° latitude, 60nm equals about 84'51" of longitude. (Or 1°24'51".)