ABSTRACT
With the R system, create maps of the world, countries, counties, cities, or smaller areas. Add additional information to a map such as population density or one of a variety of economic indicators. The Earth is almost a sphere, more accurately, but still not precisely, an ellipsoid. Yet we typically view our maps on flat surfaces such as paper or computer screen. A projection transforms spherical coordinates, which describe specific locations on a spherical-type surface, to the x,y (Cartesian) coordinates of a flat surface. A projection flattens the coordinates of latitude and longitude of the Earth's three-dimensional surface into two-dimensions.
