calculating distance between two postcodes

[merryperson]

I need to calculate the distance between postcodes to find out how far people travel.I have obtained details such as latitude and longtitude for each postcode and know it is possible to do this but how?

example of the information held

postcode x (in metres)y latitude longitude

AB10 392900 804900 57.135 -2.117

AB14 383600 801100 57.101 -2.27

EX35 272400 148800 51.224 -3.828

EX36 274300 125700 51.016 -3.792

 

 

Anyone have any ideas?

Thanks dave

[Asimov Pupil]

could you not use the arc length formula they use in calculus but i'm not sure i understand the question or the data

[Kedas]

You need to calculate the angle between those two lines (center earth to travelpoint)

then multiply the earth radios with that angle (in rad).

 

edit:

http://pollux.nss.nima.mil/calc/calc_options.html#Distance%20Calculator

some code: http://www.freevbcode.com/ShowCode.asp?ID=1793