google api for measuring distances

Hi everyone! I would like to know, if I have the coordinates of two areas, how can I take from google maps the distance, in kilometer, between them and how can i specify if it is road or sea or both that seperates them?

[Geoff Hayes]

Fivos - are you calling Google APIs directly and so have an API key to use? Or do you intend to do this some other way?

[Fivos Panetas]

I think that to get an API key is not for free, so i would like to do this some other way. If it can't be without API key, I'll get one.