The National Geographic Society unveiled a revolutionary new world map this week that shrinks the United States, depicts the continents in different proportion and provides "a more realistic view of the world."

Since 1922, the society has used maps that rely on a system developed by American engineer Alphons van der Grinten; his method was seen as the best way of meeting the age-old challenge of mapping a round Earth on a flat surface.But Gilbert Grosvenor, the president of the society, told a news conference the new map "more accurately portrays a round Earth on flat paper."

It is impossible to produce a flat map that does not distort the size, shape, distance or direction of various land masses - and van der Grinten's was no exception, for example depicting Greenland 554 percent larger than it is, the Soviet Union 223 percent larger and the United States 68 percent larger.

To mark its 100th anniversary, the National Geographic Society sponsored a competition to improve its maps. After reviewing 20 proposals, the society's panel of leading cartographers unanimously chose Arthur Robinson's method of viewing the world.

The new map makes Greenland only 60 percent larger than it is, the Soviet Union just 18 percent bigger and depicts the United States about 3 percent smaller than its actual size.

"It's a more realistic view of the world. We believe that its balances of size and shape are the most reasonable for a general reference map," said John Garver Jr., the society's chief cartographer.

Robinson, who directed the U.S. Office of Strategic Services' map division during World War II, said he decided to devise a new system after encountering many problems in mapping in a worldwide war.