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    Re: Posting Statistics / Proposal
    From: Chuck Taylor
    Date: 2001 Jul 24, 2:30 AM

    Another poster pointed out that simply averaging the latitudes and longitudes
    may not result in the most centrally located place for the meeting proposed by
    Dan Allen.  Here is another proposal for selecting a meeting location.
    
    1.  Given the lat/lon of two points, it is relatively easy to compute the great
    circle distance between those two points using the law of cosines.
    
    2.  Minimizing the average great circle distance between the meeting place and
    the the homes of list members is a reasonable criteria for selecting a meeting
    place.
    
    3.  We are not likely to meet in the middle of the ocean, but rather at one of a
    finite number of coastal or island locations such as Salem (Massachusetts, USA),
    New York, Miami, Greenwich or London, Lisbon, Copenhagen, Cadiz, Rome, Athens,
    the Azores, Bermuda, Rio de Janeiro, Capetown, Sydney, Auckland, Hong Kong,
    Honolulu, San Francisco, or Seattle.  (I'm sure readers will nominate other
    sites.)
    
    4.  Here is the algorithm, which would be fairly easy to program on a computer
    (assuming that you remember to convert between degrees and radians :-) ):
    
            a.  Let A1, A2, ..., AN be the locations (lat/lon pairs) of list members.
    
            b.  Let B1, B2, ..., BM be the locations of possible meeting sites.
    
            c.  For each i in [1:M], compute the great circle distance between site B[i]
    and each of the A[j] for j in [1:N]; average those distances.
    
            d.  This will produce a single number (average great circle distance) for each
    of the candidate locations.  Pick the site with the lowest average great circle
    distance.
    
    Any takers?
    
    Chuck Taylor
     47d 55.16N
    122d 11.18W
    

       
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