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    Geodesic versus great circle
    From: Bill Lionheart
    Date: 2018 Nov 16, 17:07 +0000

    Not exactly celnav but closely related
    
    When ships are routing they must be trying to minimize energy used (or
    a trade off between that and passage time). Obviously optimal routing
    would use prediction of wind, tide and maybe wave height. But as the
    earth is not a sphere the geodesic (shortest distance path) is is not
    a great circle.
    
    Is the difference between geodesic and great circle (around one
    percent at most I think)  insignificant compared to the variation in
    the other factors, or could ships save a worthwhile amount energy if
    they plan using the geodesic route. Given the huge energy consumption
    of ships maybe 1% is worth it? Maybe they already do it, as presumably
    big ships just use software to do routing.
    
    Bill Lionheart
    

       
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