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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Distance on ellipsoid
From: Jan van Puffelen
Date: 1996 Oct 30, 18:17 EST
From: Jan van Puffelen
Date: 1996 Oct 30, 18:17 EST
At 10:51 30-10-96 -0700, you wrote: > >If anyone is interested, I will try to find the "real" formulas. The integral VB on the ellipsoid is: VB(x)=180/pi * (LN(TAN(x)+SEC(x))-e^2 * SIN(x) - e^4 * SIN(x)^3 / 3 - e^6 * SIN(x)^5 / 5...) e = 0.08199189 (excentricity according to Hayford (International Ellipsoid)) N.B. TAN(loxodrome course) = (long2-long1)/(VB(lat2)-VB(lat1)) or better: loxodrome course = ATAN2((long2 - long1), (VB(lat2)-VB(lat1))) I use this formula to calculate loxodrome course and distance in a handheld computer but I do not bother with the excentricity. The differences between the spheroid and the ellipsoid are negligible in practice. You are very right about being careful with these formula's. But my programs (that I have provided some time ago) always give the right anwers provided N lat and E long are entered positive. Regards, Jan > >Jim > >Jim Easton >4364 Bonita Rd., No. 166 >Bonita, CA, 91902-1421 > >Tel: (619) 548-0138 >FAX: (619) 470-8616 > > > >
