I'm coding a Web App whereby users can choose their city (start) and a destination city, and find out the approximate distance between both cities, using Latitude and Longitude of both cities to calcultate. Then i thought that since this will be done using the concept of a Straight Line on a sphere, it means that i'll be getting a result of a straight line which is the shortest, but in reality (driving route especially), will have hills, curves, turns. It might be practically impossible to have an accurate distance, but how can i make the app more accurate that just a straight line distance.
I'll be most delighted by you opinions, suggestions, answers and comments. Thanks in advance.