Great-circle navigation is a method of navigation used by sailors to navigate across the globe using the shortest route possible. This method is based on the fact that the earth is not flat but instead round. It is said that sailors began using great-circle navigation in the late 15th century.
Previously, sailors would use navigational methods based on the mercator projection map, which is a cylindrical map projection that distorts the size and shape of land masses. This method was good for navigation but not for long journeys across the vast oceans.
Great-circle navigation is based on the idea that the shortest distance between two points on a sphere (such as the earth) is a straight line known as a great circle. The concept of using great circles for navigation was first proposed by the Portuguese mathematician and cartographer, Pedro Nunes, in the mid-16th century.
Sailors in the 17th and 18th centuries began using great-circle navigation to find the shortest routes across the oceans. However, the calculations required were complex and used a lot of mathematical knowledge. This made the method difficult to use and limited its use to only the most experienced sailors.
In the mid-19th century, with the development of accurate chronometers and the availability of more precise navigational instruments, great-circle navigation became more accessible to sailors. They could now easily calculate the shortest routes between two points on the globe and use this information to navigate more efficiently.
By the late 19th and early 20th centuries, great-circle navigation had become a standard method of navigation for long ocean voyages. With the development of more advanced technology, including radio communication and GPS, the method has become even more accurate and efficient.
Sailors began using great-circle navigation in the late 15th century, but it was not until the development of accurate chronometers and navigational instruments that the method became more accessible and widely used. Today, great-circle navigation remains an important tool for sailors navigating across the oceans.