iSignpost - iPhone and iPad application

Heart Directions in your hands.

Have you ever felt that strange sensation of homesickness while on trip, maybe on the other side of the world? or simply, have you ever felt that curious desire to know in which direction is placed your house? well.. this app, thanks to a digital compass, will enable you to search for the horizon in the right direction, so to feel nearer your house and your family!

We can obtain the initial course (direction) of an interesting point from the place where we are by the following.
(The formula will fail if the initial point is a pole. We don't think this will be your case).

So, for starting points other than the poles:

Of course, if the sin of arriving point, less starting point, is less than zero we remove (2 * pi ).

This formula requires the pre-computation of the distance between the 2 points. We decided to calculate this by ourself, other than use the iPhone calculated distance, thanks to this formula.

Where lat1,lon1 are the latitude and longitude of the initial point and lat2,lon2 are the latitude and longitude of the finish point.

Thanks to Ed Williams for his Aviation Formulary ( Without this we couldn't understand the course calculation theory and formulas.

We are an international Web Agency currently located in Italy. We are specialized in Web Communication / Marketing and iPhone and iPad development. To a better understanding of our services visit our website and do not hesitate to drop us an email if you have any inquiry