Saturday, March 5, 2011

World Political map

A world map is a map of the surface of the Earth, which may be made using any of a number of different map projections.
Maps of the world are often either 'political' or 'physical'. The most important purpose of the political map is to show territorial borders; the purpose of the physical map is to show features of geography such as mountains, soil type or land use. Geological maps show not only the physical surface, but characteristics of the underlying rock, fault lines, and subsurface structures.


A world map based on the Winkel Tripel projection, a low-error map projectionadopted by the National Geographic Society for reference maps.
Maps that depict the surface of the Earth use a projection, a way of translating the three-dimensional real surface of the geoid to a two-dimensional picture. Perhaps the best-known world-map projection is the Mercator Projection, originally designed as a form of nautical chart.
Aeroplane pilots use aeronautical charts based on a Lambert conformal conic projection, in which a cone is laid over the section of the earth to be mapped. The cone intersects the sphere (the earth) at one or two parallels which are chosen as standard lines. This allows the pilots to plot a great circle (shortest distance) route approximation on a flat, two-dimensional chart.