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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: query
From: Dan Allen
Date: 2002 Aug 21, 10:58 -0700
From: Dan Allen
Date: 2002 Aug 21, 10:58 -0700
On Wednesday, August 21, 2002, at 10:34 AM, Mitch B Burrill wrote: > If I am at lat1, long1, and go XXX nm at TC YYY, > What is the exact formula from spherical trigonometry to get lat2, > long2 ? > I have looked everywhere for this, I must be doing something wrong. Check out http://williams.best.vwh.net/avform.htm which has this: Lat/lon given radial and distance A point {lat,lon} is a distance d out on the tc radial from point 1 if: lat=asin(sin(lat1)*cos(d)+cos(lat1)*sin(d)*cos(tc)) IF (cos(lat)=0) lon=lon1 // endpoint a pole ELSE lon=mod(lon1-asin(sin(tc)*sin(d)/cos(lat))+pi,2*pi)-pi ENDIF This algorithm is limited to distances such that dlon