|
|
Subject: Re: Pilots and Mariners
From: Brian Whatcott (inet@XXX.XXX)
Date: Thu Feb 07 2002 - 21:59:08 EST
At 03:42 PM 2/7/02, Chuck Griffiths wrote:
>... Most
>pilots flying around the states plotting their "courses" on aeronautical
>charts
>are plotting rhumb lines on Mercator projections.
...
>they generally follow radio navigation devices that
>guide airplanes over great circle courses. Good marine navigators, of course,
>know that a radio bearing to a distant non-directional radio beacon is the
>initial bearing of the great circle track to that aid, and plot it
>accordingly.
...
>Chuck
It has already been noted that airmen in fact, plot great circles on
conical orthomorphic charts.
The straight line on the conical orthomorphic has a different starting
direction
than the end. But it raises an interesting point: there is a class of navaids
intended to indicate magnetic radial bearings - the VOR. This too radiates
great circle radials if the distance is extended far enough - so that at long
range, the indicated magnetic radial is somewhat wrong....
Brian Whatcott
Altus OK Eureka!
|