Transfer Service: How can i calculate price based on destination's coordinates?

I have a website for transfer services. (Taxis, Buses etc)

I want the user to fill a form with "pick-up" and "drop-off" location. These 2 autofill inputs (pick-up & drop-off) will connect to Google my business or places API to get the place's name + place's coordinates in hidden inputs.

We live in an island and then i want to separate the island in several pieces of areas and depending what the combination of pick-up and drop-off locations is, will show the right transfer cost.

Any ideas on how to separated the island into pieces in map (stored in my database) and then show the right cost?

• A good example for autofill inputs for pick-up & drop-off locations connecting to Google's API is on rideways.com.

• I don't want to calculate transfer cost based on distance. (km or miles) Only in which part of island is based on coordinates.

  Thank you very much!

Regards, Nick.