What distance? Air line? Or something like finding a route for some sort of transport?
Air line is a two step process: Find the geo coordinates for the address (geocoding) and calculate the great circle distance. For route planning it depends if the service you use does this for you.
That said: Look into e.g. Google Maps Api. They have a geocoding API... and methods for getting the distance, even with nice map displays, so you don't need to do any manual calculation. But there are other vendors, if the Google API restrictions are too much for you.
Joined: May 20, 2008
by walking or driving distance...
but i do not need that much details, all i need is how many kilometers between 2 post code, (this will be only used in canada)
Hauke Ingmar Schmidt
Joined: Nov 18, 2008
Walking or driving can give vastly different results (think pedestrian bridges). Google Maps API will be all you need, I think.
In Canada a postal code is a very small area, unlike the US zip code. For example the postal code where I live consists of about 15 houses on one side of a city block. So in most cases the "location" of a postal code is quite precise.