How do you get plane sailing formula?

The plane sailing formula is derived from the basic principles of navigation, particularly in relation to the relationship between distance, course, and latitude. It can be expressed using the formula: Distance = Departure / Cosine of the latitude. To apply it, you need to determine the departure (the east-west distance) and the latitude of your starting point. This allows navigators to calculate their position on a two-dimensional plane, simplifying the complexities of spherical navigation.