Читать книгу Geography For Dummies - Jerry T. Mitchell - Страница 108

A cartogram is a map in which different areas are distorted in proportion to numerical data. Following are two maps of Australia. The one on the left shows the true shape of the continent. The one on the right is a cartogram in which the sizes of Australia’s states and territories are distorted in proportion to their populations. As a result, the cartogram looks much different than the “real thing.” New South Wales, which is home to Sydney (the nation’s largest city), contains about 10 percent of the country’s territory, but about 32 percent of its population. On the cartogram, therefore, New South Wales appears bloated. In contrast, Northern Territories accounts for 17 percent of the country’s territory but only 1 percent of its population. On the cartogram, therefore, Northern Territories is quite small. These extremes visually highlight Australia’s uneven population geography. Usually, cartographers seek to minimize map distortion. In the case of cartograms, however, distortion is the purpose of the exercise.

(© John Wiley & Sons Inc.)

But that’s just this one map. On a different map, the same gray tones may mean something very different. Similarly, a light brown color may signify a particular elevation on one map, but a very different elevation on a different map. Always check the legend to make sure of the meaning of particular shades.