Ordinary compass apps can only show you the direction to another place in two dimensions — the direction of the beeline above ground. But how would you know at what angle to start digging if you wanted to dig the shortest possible tunnel through Earth from Germany to Hawaii? With this app I want to help people remember that the Earth is approximately sphere-shaped.
– Tell the app the place you’re looking for. Using the indicators on the screen, turn your phone until it points in the calculated direction.
– Move your phone around. Imagine a tunnel straight through the earth in the direction that your phone is currently pointing. A map shows you the place that lies at the end of this tunnel.