On Wed, 20 Aug 2008 16:24:31 +1000, Jim Palfreyman wrote: >Wow.
>Don't tell me people still use miles? Nautical or otherwise? >What's wrong with the good old kilometre? >Jim Jim, it is quite easy to give an answer to your question: Even using GPS geographic coordinates are still (and will be in future) in use, because the earth is a globe (even a bit deformed like a potato but is not a flat surface like a disk ;-) ! ) with a circumference of roughly 40000 km divided in 360° or 21600 (arc)min = 21600 nautical miles (NM or nmi). Nautical charts are divided in degrees and minutes by a grid of intersecting lines thus allowing very easy and quick to measure distances positions and passages just applying a nautical divider (attn.: to me adjusted o n l y on the right or left side of the chart, the meridians N or S value!) To avoid nm (nanometers) with nautical miles: The preferred abbreviation of the IEEE is nmi For aviation use, the preferred abbreviation of the ICAO is NM A nmi = 0.9998834 mean meridian arc minutes = mean historical nautical miles (approx.) In 1929 when the International Extraordinary Hydrographic Conference held in Monaco was adopted a definition of one (1) international nautical mile as being equal to 1,852 m exactly. more eg.: http://en.wikipedia.org/wiki/Nautical_mile http://encyclopedia.farlex.com/nautical+mile http://citadelnavy.files.wordpress.com/2008/02/02-terrestrial-coord-sys-charts.ppt I think even in 'modern' times the use of nmi will therefore not disappear! regards Arnold _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.