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Re: Figuring Course given Lat/Long of destination
From: Ed Kitchin
Date: 2000 Feb 28, 7:09 AM
From: Ed Kitchin
Date: 2000 Feb 28, 7:09 AM
Thank you, Tony. In other words, I could construct a solution on the univ. plotting sheet, as I mentioned, but use the mean of departure, and destination latitudes, and that would work? Thank you. Ed ----- Original Message ----- From "Tony"To: Sent: Sunday, February 27, 2000 9:00 PM Subject: Re: Figuring Course given Lat/Long of destination > Ed: > > When you say that "there is the error of the Macerator thing", can you be > more specific? Did you use Bowditch Mercator sailing by tables? This > should work out OK. > > Actually, just using Plane sailing with mid-latitude should be quite close > because the distance is relatively short; only earth eccentricity is ignored. > > Why the problem suggests also GC (great circle) does not make much sense. > There would be less than a mile difference. I did check the results by > computer and they are OK. [ Sometimes they are not. ;) ] > > Tony in San Francisco > > > > Ed Kitchin wrote: > > > > An interesting problem appears in the latest issue of "Ocean Navigator" Which asks that you figure > > the course to a destination given origination and destination. It would seem easy to determine the > > difference in lat. (The destination was over several degrees of lat.), but deg. of long. differ in > > length as you change lat. One could simply take the mean of the two given long. and use that, but > > that bothers me as not being all that accurate. There is the error of the Macerator thing. You > > could use universal plotting sheets and construct using a vertical representing diff./lat., then > > draw a horizontal from the top of the lat. fig., representing the long. at the destination, and > > draw a hypotenuse as the course line. (???) Are there any mathematicians out there to > > give me a good formula to learn for this task? Thank you. > > > > Ed Kitchin >