A physical map primarily focuses on the world's ecological formations and topography. These type of maps concentrate on the world's seven continents – Africa, Antarctica, Asia, Australia, Europe, North America and South America – and four oceans: Atlantic, Arctic, Indian and Pacific. Special user groups such as seismologists, petrologists, sailors and meteorologists rely on physical maps for their professions. For example, when seismologists attempt to locate the origin of an earthquake, knowing the area's geographical features is more helpful than its state or county boundaries.
Political maps do not focus on the continental divisions of the world, but the boundaries of the continent's nations and states. These types of maps also show districts such as counties, territories and prefectures. Political maps label the cities and towns within a country or state's districts. More detailed political maps show the voting districts (in nations that allow voting) or plane routes. Certain countries will not allow airplanes from other countries to enter their nation, thus no air routes exist into their countries. Many political maps feature latitudinal and longitudinal lines, which help map observers locate a certain country or city.
Invited by Flemish mapmaker, Gerardus Mercator, the Mercator Projection map is designed to guide sailors through the world's oceans and seas. The Mercator Projection map helps because of its rhumb lines, or lines that pass by all the world's longitudinal lines at the same angle. As a result, the map has a cylindrical shape and all the latitudinal lines have the same length as the Equator. However, the Mercator Projection map also causes distortion in the sizes of land masses; for example a Mercator Projection shows Greenland is the same size as Africa. Consequentially, these maps are primarily used for nautical navigation, but as standard physical maps.
With the advent of computers, many modern cartographers create electronic maps. Electronic maps are able to implement political and physical information about the world's geography. Two types of electronic maps currently exist, a Raster map, which is an electronic picture of a paper map, and a Vector map, a map with information on road structures, traffic flow directions and city names. A Vector map is commonly seen in Global Positioning System devices, also known as GPS. Since road networks change periodically, electronic map companies constantly update their maps.
