Re: [Re: calculating distance based on zip/postal codes]

Zach Kenyon wrote:

> D= 6,370,997*arcos(sin(LAT1)*sin(LAT2) + cos(LAT1)*cos(LAT2)*cos(LONG1-LONG2))
> WHERE: 
> D = distance in meters 
> LAT1 = latitude of point1 (in radians) 
> LONG1 = longitude of point1 (in radians) 
> LAT2 = latitude of point2(in radians) 
> LONG2 = longitude of point2 (in radians)

Ah Ha !!
So now you assume I know the long/lat of my house and the long/lat of the
city hall in the next zip code ?

If we use the web411 URL suggested by Chuck, we find this warning =

*The distance calculated is approximate since each ZIP Code area can be many square 
*miles.
*The distance is calculated from the population weighted centroid of each ZIP Code.
*The distance is "as the crow flies" and does not take into consideration bends and 
*curves in the roads.

That is NOT what Susan asked. She wants the distance between two points using zip
codes as reference, and I still say you can't do that on anything other than a very 
general basis.

Loved your message though Zach, and it reminded me of why on the ship we
used these neat little machines called GPS. Where you look in a book for the long/lat
of some lighthouse, harbor entrance, or whatever - punch that in and find out how far it 
was, in what direction, how long to get there,  and exactly where was I in relation to 
it.   Easy.


Capt. Ron
http://www.novagroup.org

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