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Maps and the Ideas they Express

Twentieth Century: Changing Technologies

These advances continued and accelerated in the twentieth century through such developments as the airplane and Figure 10. Section of William Smith's geological map of England (1815). photography in the first half of the century; and space probes and more exotic imaging in the second half.

Controlled flight.

Although balloons were used earlier, it was only after the development of controlled flight, through the airplane in the first decades of the twentieth century, combined with viable photography, that the new science of photogrammetry could be realized. Overlapping vertical aerial photographs could be taken at regular intervals, which, when viewed through a stereoscope, give a remarkably accurate three-dimensional view of Earth. This greatly facilitated geodetic and contour mapping, which gradually displaced other, less quantitative methods of relief representation. As photogrammetry progressed it provided a basis for mapping that was more accurate than was possible previously, and could be accomplished in much less time. It was also possible to map areas without the necessity of field work except perhaps, when feasible, for checking. Such mapping required a big capital investment, so that it became a largely national enterprise, with richer countries sometimes undertaking aerial surveys for poorer ones.


In the second half of the twentieth century (partly as a result of German advances in rocketry in the first half), as well as indigenous programs in those countries, Russia and the United States became the protagonists in a "space race." But it was the more peaceful applications that advanced cartography particularly. The first science to be improved was meteorology, as weather maps produced on a daily, or an even shorter time frame, revealed patterns that had not previously been appreciated, as well as facilitating weather forecasting on a regular basis. But soon other distributions, such as land use, were imaged and monitored. This was made possible by the Landsat program of the United States, whose low-resolution imagery was made available to all countries. Remarkable Russian contributions included the first images of the previously unobserved side of the Moon. Soon the United States landed humans on this body, from which images of the whole of planet Earth were made. A great many different parts of the electromagnetic spectrum were utilized in space imaging: color, color infrared, ultraviolet, microwave, radar, and so forth, which either singly or in combination revealed remarkable patterns on Earth, and on extraterrestrial bodies. Other countries such as France concentrated on space imaging of smaller areas of Earth with higher resolution. The new science was designated "remote sensing" of the environment.

Topographical and geological mapping.

From the earliest years of the twentieth century there had been a desire to have uniform map coverage of the globe. This was proposed by Albrecht Penck (1858–1945), and it became formalized as the International Map of the World (IMW) on the scale of 1:1,000,000 (one unit of the map equals one million units on the Earth). Although supervised by the League of Nations and (partly because some countries failed to cooperate) later by the United Nations, the project was never completed. However, during World War II such coverage was compiled as the World Aeronautical Chart (WAC), and the two projects combined under the supervision of the United Nations (Fig. 11).

Along with these international efforts at mapping, the nations of the world continued their own cartographical activities including, especially, the production of topographic and geological maps. But on a global basis that coverage is very uneven. The same is true for urban population and transportation mapping, which is largely the responsibility of local agencies, or even private bodies. For example, the automobile or road map, an extremely important cartographic form, is mainly undertaken by oil or tire companies, or by automobile associations in the United States, and other countries. Maps for classrooms and for other educational purposes, in most countries of the world, are likewise the concern of private map companies. This has made commercial cartography highly varied in quality, but also sometimes surprisingly innovative. It is unlikely that government-sponsored cartography alone would have produced such artistic products as the global-perspective renderings of Richard E. Harrison, the natural color relief maps of Hal Shelton, or the simulated three-dimensional isometric urban cartography of Herman Bollmann. Similarly, the statistical maps of Lászlo Lácko or the economic maps of W. William-Olsson are the product of freelance or university-based cartography. Likewise some of the most innovative projections of modern times are the work of non–government employed cartographers, including in the United States, R. Buckminster Fuller and J. Paul Goode, but such individuals are sometimes funded by government grants. The printing of maps was also advanced by color photolithography from high-speed presses at this time.

Exploration and mapping.

In the twentieth century two large realms of Earth were systematically explored and mapped: the polar areas and the deep oceans. This was made possible by modern technology and, often, great human effort. Although the Northeast Passage (north of Asia) was navigated by the Baron Nils Adolf Nordenskiöld (1832–1901) in 1878–1879 in his ship Vega, the Northwest Passage (north of North America) was not traversed completely by ship until 1903–1906, by Roald Amundsen (1872–1928). The North Pole, or a close approximation to it, was attained over land and ice by Robert Peary (1856–1920) and the African-American Matthew Henson in 1909. These explorers were too rushed to engage in mapping, but they were later followed by aviators who had cameras and better views of the polar landscape, provided by the airplane. Nordenskiöld spent his later years collecting and studying old maps (an interest of many professional cartographers, and others).

Antarctica was little known until the twentieth century, when explorers from a number of countries made concerted efforts to explore and map the "Great White Continent." Amundsen reached the South Pole in late 1911, and Robert Scott (1868–1912) and his party died in returning from his attempt early the next year. These efforts did not lead immediately to a profound understanding of Antarctica, which was greatly advanced, however, by cartography during the International Geophysical Year (IGY) in 1958. This enhanced knowledge was made possible in part by photogrammetry, as was the 1953 conquest of Mount Everest by Edmund Hillary and the Sherpa Tenzing Norkey (1914–1986) a little earlier.

Another realm, the world's oceans, has also yielded its secrets grudgingly. Except for coastal areas, little was known of the oceans' depths until sonic sounding (from c. 1950 on) revealed the rich variety of forms of this greater part of Earth's lithosphere. The continuous trace, or profile, which is recorded Figure 11. Map of Los Angeles, California, derived from the International Map of the World. U.S. GEOLOGICAL SURVEY while a ship is in motion by sonar can be converted into map form revealing, for example, the profound deeps and continuous ridges of underwater areas. This cartography also confirmed the highly controversial, but now generally accepted, theory of continental drift or displacement. Cartography is so important that it can be said that a geographical discovery may not be accepted as valid until it has been authenticated by mapping.

Computer mapping.

There is a close correspondence between progress in cartography and the general development of science and technology. Thus, the computer has transformed cartography since the early 1980s as much as, or more than, printing, flight, and photography did at earlier times. The computer permits manipulation of large data banks and the production of maps made without benefit of hands. Is also facilitates the making of animated maps for illustrating the dynamics of areal relationships. In this way a fourth dimension has been added to cartography—time. More maps are probably now viewed on screens, whether animated or not, than in any other medium.

This short survey of cartography has discussed how maps have conveyed ideas and represented phenomena of a wide variety of distributions. They have recorded important achievements of humankind from considerations of the shape of the earth to setting foot on the lunar surface. Preliterate as well as advanced societies have contributed to the art and science of mapping. In fact, cartography is a barometer of the progress of humankind and a reflection of changing technologies. Thus it has been advanced by inventions such as printing and flight, but also by geographical exploration and statistical methods. In the twenty-first century further dramatic developments in this ancient field of endeavor will continue and increase.


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Norman J. W. Thrower

Additional topics

Science EncyclopediaScience & Philosophy: Macrofauna to MathematicsMaps and the Ideas they Express - Preliterate And Early Literate Maps, Printed Maps Of A More Detailed Globe, Nineteenth Century: General And Thematic Mapping