This is a tech demostrator page.

The data for the map is gained from what a browser sends to the website plus local geodata. The Visitor's IP address is extracted, then sent to an off site translator database where IP address is translated into coordinates, and then sent back to this website. That data, combined with the local geolocation data, is sent to Google Maps to generate a static map image and return it to the originating website.

Distance between the two points is a geometric mathmatical formula based on the coordinates, used to calculate distance as a partial arc of circumference of the earth.