Calculate distance between 2 GPS coordinates

Question

How do I calculate distance between two GPS coordinates (using latitude and longitude)?

Answer 1

It depends on how accurate you need it to be, if you need pinpoint accuracy, is best to look at an algorithm with uses an ellipsoid, rather than a sphere, such as Vincenty's algorithm, which is accurate to the mm. http://en.wikipedia.org/wiki/Vincenty%27s_algorithm