How to calculate the distance between two cities ?
The formula used to calculate the distance between two geographical points is called orthodromy, it is defined as follows : Distance(A,B) = 6371 * ACos( Cos(LatA) * Cos(LatB) * Cos(LngB – LngA) + Sin(LatA) * Sin(LatB) )The resulting number is the distance in kilometers between point A and point B. If you wish to return a result in miles (or any other unit), you must substitute the value 6371, which stands for the approximate radius of the Earth in km, by its equivalent in miles (or any other unit), that is 3959 miles. Latitude and longitude values must be input in radians : radians = degrees * PI/180. Excel template is available here.
