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    Re: Location Center of Responses thus Far
    From: Glendon
    Date: 2001 Jul 23, 7:04 PM

    Its an optimisation problem isn't it?
    
    Let x be the unknown location centre
    Let D(i) be the great circle distance between the i th member and x
    Then we want to choose x such as to:
    minimise{sum of [ D(i); i=1-n]}
    
    or, minimise{sumof[ square of D(i): i=1-n]}
    subject to x lying between lat and lon of 0-360
    
    hmmm, shipping or airline companies must have tackled this one??
    Lee Martin
    ----- Original Message -----
    From  "Dan Allen" 
    To: 
    Sent: Tuesday, July 24, 2001 7:23 AM
    Subject: Location Center of Responses thus Far
    
    
    > The following people have replied so far to my request for location:
    >
    > NAME             LAT     LON
    > ================================
    > Allen Dan        47.482  121.798
    > Arrouye Yves     37.892  122.997
    > Emerson Rick     40.245   75.252
    > Gilbert Greg    -35.167 -138.75
    > Hogan Dan        33.147  117.958
    > Huxtable* George 51.6      1.28
    > Murdoch* Bill    36.548   82.562
    > Ouvry Philip     42.43    -3.15
    > Sher* Russell   -33.933  -18.367
    > Simmonds John   -37.353 -143.635
    > Smith Peter      42.217   71.283
    > Talge Gordon     34.052  117.253
    > Taylor* Chuck    47.9    122.3
    > Tripp Steven     37.5   -140
    >
    > * = Position approximated by looking up city in Encarta World Atlas
    > (North and West are positive, South and East are negative)
    >
    > Using these 14 data points, the average latitude is 24.6 North,
    > and the average longitude is 27.7 West, a spot 487 nautical miles
    > north of Mindelo, Cape Verde islands in the central Atlantic ocean.
    > This is quite a distance from the nearest restaurant.
    >
    > The nearest spot on a continent is Nouakchott, Mauritania, 761 nmi SE.
    > It is 1177 nautical miles NE to Casablanca in Morocco.
    >
    > Hmmmm...
    >
    > Daniel K. Allen
    > danallen{at}nwlink.com
    > http://www.nwlink.com/~danallen/
    > Measure | Analyze | Communicate
    >
    

       
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