by Dr. Peter Wayne
There's been a flurry of interest in great circle calculators. A great circle is the shortest distance on a sphere between any 2 points, and that explains why flights from New York to London fly over Newfoundland. There are excellent Web references to great circle calculations, and I have provided a few in the Xdialog that accompanies this article.
This Great Circle calculator also uses a 1999 U.S. Census list of zip codes to provide distances between any 2 U.S. zip codes. Of course, the list is neither complete nor up-to-date, but that's up to you and the Census Bureau to argue over. If you need an updated zip code and latitude/longitude list for your business, there are a few internet sites that offer a subscription service for just this purpose.
Here is the Great Circle calculator with the coordinates of LAX and JFK:
Fig. 1. Coordinates of Los Angeles International Airport and John F. Kennedy International Airport.
And here is the distance from Yonkers, NY to Cambridge, MA:
Fig. 2. Distance between 2 zip codes.
Download the zip code table and great circle script used in this article.
7/12/2003
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