Clarion in general: Calculate distance based on global position 2006-06-09 -- Len Lutz > Where did you find the formula to calculate distance? I have looked at > the > database from zipcodeworld, the data is there but we would need to be able > to do that distance calculation. For calculating distance, try this code. I have found it gives me pretty accurate "DRIVING" distances (in miles) between two zipcodes (Latitudes/Longitudes of zipcodes). If you want the actual, straight-line distance between the centers of the zipcode areas, remove the " * 1.28" at the end of the last line. =================================== GetDist PROCEDURE (SREAL Lat1, SREAL Lon1, SREAL Lat2, SREAL Lon2, *SREAL Distance) rLat1 SREAL rLon1 SREAL rLat2 SREAL rLon2 SREAL Deg2Rad EQUATE(0.0174532925199e+000) CODE rLat1 = Deg2Rad * Lat1 rLon1 = Deg2Rad * Lon1 rLat2 = Deg2Rad * Lat2 rLon2 = Deg2Rad * Lon2 Distance = (3963.1 * (ACOS(SIN(rLat1) * SIN(rLat2) + COS(rLat1) * COS(rLat2) * COS(rLon2 - rLon1))) * 1.28) Printed November 21, 2024, 11:19 am This article has been viewed/printed 35218 times. Google search has resulted in 18 hits on this article since January 25, 2004. |