April 10, 2011 07:41
Ron,
For short distances between 60ºN and 60ºS:-
The distance run between 2 waypoints is roughly equal to the square root of (the difference in Latitudes squared plus (the difference in Longitudes times the departure at mid Latitude) squared);
D=sqrt((L2-L1)^2 + ((Lo2-Lo1)*cos(L1+(L2-L1)/2))^2)
The course is approximately equal to the angle whose sine is (the difference of Latitudes divided by the distance run)).
c=asin((L2-L1)/ D )
The course © must be corrected for quadrant and the latitudes and longitudes must be in the same hemisphere.
For great circle computations:-
D=60*acos((sinL1 * sin L2) + (cosL1 x cosL2 x cos t)]
C=asin[(cosL2 * sin t)/(sin D)]
For details and limits, please refer to
Dutton's Navigation and Piloting, page 661 paragraph 2914, "The Sailings"
For short distances between 60ºN and 60ºS:-
The distance run between 2 waypoints is roughly equal to the square root of (the difference in Latitudes squared plus (the difference in Longitudes times the departure at mid Latitude) squared);
D=sqrt((L2-L1)^2 + ((Lo2-Lo1)*cos(L1+(L2-L1)/2))^2)
The course is approximately equal to the angle whose sine is (the difference of Latitudes divided by the distance run)).
c=asin((L2-L1)/ D )
The course © must be corrected for quadrant and the latitudes and longitudes must be in the same hemisphere.
For great circle computations:-
D=60*acos((sinL1 * sin L2) + (cosL1 x cosL2 x cos t)]
C=asin[(cosL2 * sin t)/(sin D)]
For details and limits, please refer to
Dutton's Navigation and Piloting, page 661 paragraph 2914, "The Sailings"
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Jon Longworth
Jon Longworth