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This is my first question here, hopefully it fits.

Imagine all people on the northern hemisphere are looking North to the Pole. Now I want them to look towards a new location given by latitude, longitude. How do I calculate the rotation needed (3D space) for each individual?

So far I've figured everybody standing on a line going through both points need to rotate by PI if standing between and everybody outside by zero.

And for everybody the two points are at a 90° angle the rotation is PI/2 or -PI/2 on the other side.

I believe min max rotation is -PI and PI. How do I build a formula solving this problem for all points?

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1 Answer 1

  1. Calculate the distance from your initial point to the north pole.
  2. Calculate the distance from the north pole to your new point on the sphere.
  3. Calculate the distance from the new point on the sphere to your initial point.
  4. Use http://en.wikipedia.org/wiki/Spherical_law_of_cosines
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Thanks, exactly what I needed. –  noiv11 Jun 2 '12 at 22:49
    
@noiv11: OK, great! Also, if you have no further remarks or questions please accept the answer above such that the question gets a closure. –  M.B. Jun 2 '12 at 22:56
    
It works only on the left side when looking from NP to new pole. Any idea? –  noiv11 Jun 3 '12 at 22:19
    
@noiv11: what do mean? –  M.B. Jun 3 '12 at 23:15

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