Author

Topic: nautical mile

cuniverse

posted January 31, 2010 11:16 AM
how do you calculate the nautical miles between N15Deg 150W to N15Deg 165W on Latitudinal plain


David Burch

posted January 31, 2010 11:48 AM
"...N15Deg 150W to N15Deg 165W on Latitudinal plain"
we have various calculators online that do this, but the short answer on the same lat line, for a short distance it would be just (Lon difference in minutes) x cos (lat)= 15x60xcos(15) = 869.33 nmi.
this is essentially a mercator result. it would be 869.16 nmi by GC
do a search to find our NIMA calculators to check the latter.
note that for a longer distance the CG difference will be larger, esp at higher latitudes.
Also if you really want to do this most precisely, you have to use ellipsoidal distances that depend on the chart datum, and we have a calculator for that online somewhere as well.
From: Starpath, Seattle, WA


David Burch

posted January 31, 2010 11:55 AM
Remember too, that you can always find mercator or rhumbline distances by just using your dividers on a chart and walk off the distance. No math required at all.
and you could even do this with a universal plotting sheet if you did not have a chart of the region of interest.
From: Starpath, Seattle, WA


