Map Projections - Part I

July 27, 2002 -- Developing Map Projections with Java. In this first article of a multi-part series, an interface for computing different map projections is presented as well as a skeletal implementation of the interface. VR

Finding your way around an unfamiliar area has always been difficult. Often you need to ask someone how to get from where you are to where you want to go. After much gesturing and describing landmarks which you were probably not aware of, they may grab a scrap of paper and sketch out streets, and maybe a few bridges or large buildings to help you find your way.

The creation of maps to guide travelers has a long history. It is known that maps were in use around 150 BC, but it would not be unreasonable to speculate that maps existed long before that time. During the 1500s maps where developed to assist sea captains in finding their way between distant ports. The premier map maker of that day was Gerardus Mercator (1512-1594). He developed a map projection that shows locations at their true direction and distance. These maps were extremely useful for ship captains finding their way by spotting various land marks and direction from their line of travel. The major navigational feature of the Mercator projection is that the sailing route between two points is a straight line if the direction of the ship's course remains constant with respect to north. The Mercator projection is the standard used for nautical charts to this day.