I want to calculate shortest paths on some kind of already existing map API routes and then draw them.
That being said, I need to be able to extract/get as more more data as possible (i.e. routes' coordinates) in order to be able to manipulate with it.
My first thought was using Google Maps but as far as I understand, Google Maps API provides very little necessary data for my problem thus I won't be able to make any kind of accurate calculations. Also, existing Google Maps API's algorithms does not concern me because I want to implement my own and test them.
Then I looked to Openstreetmaps but it's documentation also talks very little on the subject and I still don't know if it is possible to do such calculations.
So, still not ruling out Google Maps and Openstreetmaps, my question would be - what existing map API would be best for me not only to calculate shortest paths but also to represent them on it?