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    Re: Position from altitude and azimuth.
    From: Bill Lionheart
    Date: 2020 May 19, 09:00 +0100
    So the discussion Frank and I were having off list is how how to turn this in to a proof that the isoazimuth is a small circle. My idea is to use stereographic projection. This takes the upper hemisphere to the plane, it maps circles to circles and preserves angles as it is a conformal map. 
    I may be missing something as I am suspicious that I can't see the result in the literature.
    It should be possible to do it analytically as well, ie show that the formula for lat and long if a point on an isoazimuth lies on a small circle.

    Bill

    On Tue, 19 May 2020, 08:17 Frank Reed, <NoReply_FrankReed@fer3.com> wrote:

    Here's a better version of my sketch from my earlier post.

    Frank Reed

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