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As the crow flies

Determines the shortest distance between two points on a map
  [vote for,

Input: Address, City, State/Province, Country of points A & B
Output: Addresses = Global Positions > Distance between two points = As the crow flies
thumbwax, Sep 06 2002

great circle mapper http://gc.kls2.com/
it helps if you know your airport codes [mihali, Sep 06 2002]


       Erm? Is this deliberately vague so that people will suggest what they think you mean and then you say..."That's it!"?   

       If so...Is this meant to be some kind of GPS add on that does the vector mathmatics of subtracting A^ from B^ and then accounting for curvature of the Earth to output a distance and direction?   

       Or just a reminder of the definition of the phrase "as the crow flies"?
Jinbish, Sep 06 2002

       I would call this device a 'human'.
Input to 'human'= a decent atlas, a ruler, and an understanding of how map scales work.
Output from 'human'= fairly rapid deduction of shortest distance between two points. At worst some scribbling to be undertaken on napkin or convinient back of envelope .
Zircon, Sep 06 2002

       This can be acheived in UK using the PAF (Postcode Address File) available (at great cost) from the Post Office. Each UK postcode (there are ~1.7 million) has an associated X- and Y- grid reference, so with a bit of Pythagoras the distances between any two addresses can be calculated.
For non-crow distances, there are several products out there (MapInfo's Drive-Time springs to mind) which take account of annoying details like roads.
I assume that all countries have their own equivalents of PAF; I know that USA, Canada and Australia have.
angel, Sep 06 2002

       Point A to Point B - is there a generator/translator that does this on the web?
thumbwax, Sep 06 2002

       tw: try the great circle mapper (see link). you just enter the airport codes of the cities invovlved, and it gives you the distance between. i think you can also input co-ordinates of some kind, but i'm not sure. i'm a little new to it myself.   

       <after some browsing...> from the great circle mapper:   

       Is there a simple way to compute great circle distances?   

       Assuming Earth is a perfect sphere of radius 6371.2 km, convert longitude and latitude to radians (multiply by pi/180), then compute as follows:   

       theta = lon2 - lon1
dist = acos(sin(lat1) × sin(lat2) + cos(lat1) × cos(lat2) × cos(theta))
if (dist < 0) dist = dist + pi
dist = dist × 6371.2

       The resulting distance is in kilometers. lon=longitude, lat=latitude
mihali, Sep 06 2002

       Can't you just tie some string to a crow, and try it out for real?
DrCurry, Sep 06 2002

       Autoroute 2000 can do this to +/- 1km for most of Europe. I think it uses the WGS84 GEoid (same as for GPS) so it's pretty accurate. So I guess this is Baked.
8th of 7, Sep 06 2002

       Kewell - I'll leave this up long enough for anybody to take advantage of the links. My search apparently used wrong terminology. Thanks (Don't understand why such an idea would get a fishbone - jealousy, perhaps - yeah, that's it - jealous, jealous, jealous)
thumbwax, Sep 07 2002

       all around us are little green men.
po, Sep 07 2002


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