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    Re: The Nautical Mile?
    From: Paul Hirose
    Date: 2020 Oct 31, 22:07 -0700

    For the radius of curvature R of the meridian at a given latitude,
    Special Publication No. 8 (Formulas and Tables for the Computation of
    Geodetic Positions, 7th ed.) of the US Coast & Geodetic Survey gives this:
    
    e2 = (a^2 - b^2) / a^2
    
    R = a * (1 - e2) / √(1 - e2 * sin^2 φ)
    
    where
    
    a = ellipsoid major axis
    b = semi-major axis
    φ = latitude
    
    For instance, if a = 6378.137 km, b = 6356.752 km, φ = 30°,
    
    e2 = 6.694 478e-3
    R = 6340.747 km
    
    --
    Paul Hirose
    http://sofajpl.com/
    

       
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