Maps and the Ideas they Express

Norman J W Thrower. New Dictionary of the History of Ideas. Editor: Maryanne Cline Horowitz. Volume 2. Detroit: Charles Scribner’s Sons, 2005.

Cartography, the art and science of mapmaking, began before the invention of writing and continues to be fundamental to an understanding of the phenomena it represents graphically. Although typically associated with Earth, or parts of this body, its methods are applicable to the delineation of both the microcosm and the macrocosm. Thus, there is mapping of the human brain on the one hand, and the mapping of extraterrestrial space on the other. The unifying concept in mapping is the representation of spatial relationships and their interactions, and nowhere are these approaches more important than in geography. This entry will be concerned mainly with the map as it relates to physical and human geography, although some attention will be paid to extraterrestrial mapping. There will also be some references to GIS (geographical information systems); remote sensing of the environment through aerial and space imagery; and computer graphics (including animation). These are the twenty-first-century developments of more traditional forms of cartography. As Marshall McLuhan has expressed it, maps are one of a select group of media, “without which the world of science and technologies would hardly exist.”

Preliterate and Early Literate Maps

The so-called Bedolina petroglyph can be used as an example to illustrate preliterate mapping. This rock carving represents a known, inhabited site in northern Italy and was carved between 2000 and 1500 B.C.E. It was made in different stages in the Bronze and Iron Ages; interestingly, the more abstract symbols (tracks and field boundaries) appear to come from the earlier period, while the more realistic symbols (animals and structures) are from the later epoch. In any case, this plan attests to the basic importance of maps to humankind from early times and illustrates symbolization and other essential map features.

Other examples of preliterate cartography could be cited, but only a small number of such early maps have survived. A much larger corpus of maps of preliterate peoples of later times exists. In Russia in the early part of the twentieth century, a collection of more than one hundred so-called “native” maps was assembled, which included examples from Asia, America, Africa, Australia, and Oceania. They were employed for widely different purposes—from oceanic navigation to ceremonial uses. Likewise, the materials used were diverse, according to those commonly within the resource base of the makers: stone, wood, animal skins, either painted with locally available pigments or carved. It is known that “primitive” societies made maps for practical uses, but also for religious and nonutilitarian purposes.

Similarly, the maps of literate peoples in antiquity are varied in terms of purpose as well as materials employed. They are also more diverse in subject matter than earlier ones: a detailed plan of a garden, c.1500 B.C.E.; a zodiacal map carved in stone, c.100 B.C.E.; and other examples from ancient Egypt. Also from this culture and period are maps on the bases of coffins, which served as “passports” to the world beyond. A very different cartographic genre was the cadastral or land ownership plan, from which it is inferred geometry arose as such property maps, made originally for taxation purposes, were used to reconstruct boundaries, erased by the flooding of the Nile.

Contemporaneous with these Egyptian maps were those from Mesopotamia, mostly using cuneiform symbols on clay tablets. This cartography, however, varied widely according to subject matter and scale: city plans; maps of the rivers Tigris and Euphrates with the surrounding Armenian mountains; and a “world” map featuring a circumfluent ocean, with distant places represented by triangles—only one of these triangles is now intact. The circumfluent ocean, shown by a circle, is a reminder that the sexagesimal system of dividing this figure, the usual mode employed in mapping to this day, came to the West from Babylon by way of Greece. Babylonian maps also contain written inscriptions.

Earth As a Perfect Sphere and Map Projections

In Greece the idea of Earth as a perfect sphere developed gradually. This concept was not, apparently, part of the culture of Egypt or of Mesopotamia, where a plane figure was used to represent the world. By contrast, once the Greeks accepted the idea of a spherical Earth, they attempted to divide the globe in different ways. They recognized parallel climate zones and antipodes, and measured the circumference of the entire globe. The most successful attempt of this last was by Eratosthenes (c. 276-c. 194 B.C.E.), who, it is estimated, came within two hundred miles of the correct size of the Earth, a great triumph of antiquity. These developments made possible the invention of map projections (a systematic arrangement of the meridians and parallels of the all-side curving figure of Earth) of which two are credited to Hipparchus (2nd century B.C.E.). He espoused a smaller measure of Earth than that of Eratosthenes, and his projections, the azimuthal (radial from a point) and the stereographic (in which the circles of the Earth are represented by circles on the projection) were at first used only for astronomical purposes.

It is unfortunate that only a few examples of maps of the early Greeks have survived, because their theoretical ideas on geography (expressed in contemporaneous literature) as on many subjects, are of great importance. Apart from maps on a few early Greek coins, one must await the advances of the later Greeks, and the Romans, for visual evidence of their cartographic skills. The greatest cartographer of this later period is the Greek Claudius Ptolemy (2nd century C.E.) who worked in Alexandria and was not, presumably, related to the Egyptian dynasty of that name. Ptolemy (Ptolemaios) accepted a “corrected,” shorter figure of Earth than that of Eratosthenes, which Ptolemy also used as a base for two conic-like projections he devised. It is not certain whether Ptolemy actually made maps himself, but his list of the coordinates of some eight thousand places and his instructions for mapmaking provided the means for others to do so. In fact, the Ptolemaic corpus was transmitted via Byzantium to Renaissance Italy, where maps were compiled from this much earlier source material. Ptolemaic maps cover about a quarter of the globe, including parts of Europe, Asia, and Africa (Fig. 3). Ptolemy devised both chlamys (cloak-shaped) and simple conic-like projections for his world maps.

Some later Greeks worked under Roman masters, who generally accepted Greek ideas; but the Romans were themselves responsible for mapping some areas not part of the Greek empire, such as Gaul (France). Eminently practical, the Romans extended their rectilinear cadastral surveys (centuriation) over large areas from Britain to North Africa and made maps of their road systems. A remarkable example of the latter is the Peutinger Table (a fourth-century copy survives of this first-century C.E. itinerary map). Some of these ideas filtered down in the Middle Ages to Europeans, who were also consumed with religious iconography on their maps.

Sacred and Secular Maps

The most important survivor of this genre is the (East-oriented, East at the top) Hereford Mappa Mundi. Made around 1300 C.E., this map of the world known to Europeans in the later Middle Ages combines concepts both sacred and secular and was apparently used for didactic purposes. In addition, there were maps for pilgrimage, which, like the maps of the then-known world, were products of monasteries. Contrasting with this cartography are the portolan (haven-finding) charts of the same period covering the Mediterranean and Black Seas, later extended beyond the limits of these littoral areas. Portolan charts were based on the directions of the magnetic needle, which had apparently been transmitted westward from China, via the Arabs, to the Mediterranean. There, in the later Middle Ages, it was combined with a card of the Greek system of wind directions to produce the magnetic compass. Made with the use of the magnetic compass, the portolan chart features the compass rose, emanating from which are rhumb lines to points of the compass: four, sixteen, and finally thirty-two. The North-oriented portolan charts were of great value in navigation within the Mediterranean but were of lesser use in areas where the cardinal direction of the compass varied greatly from North. The Europeans were soon to encounter such areas in their expansion to the Atlantic Ocean and beyond. Remarkably, portolan charts can be attributed to Christian, Islamic, and Jewish cartographers, sometimes working together.

China and the Arab World

From very early times there was interest in the representation of Earth in the Orient, and there are remarkable parallels between mapmaking in this region and in the Greek world and the Latin West. In the later classical period there was intermittent contact between China and Rome, and most of the then-current cartographic forms are present in both cultures, including maps of land areas and marine charts. In fact, during the European Middle Ages, China was ahead of the West. Thus the most accurate map of a large geographical area was of China (c. 1100 C.E.), which utilizes a rectangular grid, and depicts the coasts and rivers of the country with great accuracy. Chinese sea charts were at least equal in quality to those of Europe at the time. In addition, map printing in China anticipates that of the West by at least three centuries. However, after 1450 C.E. when long-distance voyaging, which had taken the Chinese to the Persian Gulf and East Africa and perhaps further, was officially discouraged, Oriental mapping became extremely Sino-centric, with the rest of the world represented as peripheral to China. This influence also persisted in Korea and Japan where, however, some innovations in mapping took place especially in the delineation of urban areas and of administrative divisions.

The Arabs, especially after the rise of Islam (7th century C.E.), traveled widely from Iberia to the Orient to proselytize and trade. By sea they reached India and established settlements there and on the coasts of China; overland they controlled a large area from Spain to the Far East. They also inherited Ptolemaic cartographic (and astronomical) ideas, and improved upon them. Thus, to take one notable example, Abd-Allah Muhammad al-Sharif al-Idrisi (1100-1154) made significant contributions to cartography. Born in Morocco, Idrisi, after having traveled extensively, was invited to Sicily by its enlightened Norman king, Roger II. Under this patronage, Idrisi compiled South-oriented maps: of the world known to twelfth-century Islamic travelers, in multiple sheets; a single sheet map of Asia, Europe, and North Africa with parallels on the Greek model of “climata”; and a book of sea charts of use to sailors, “the Sons of Sindbad,” and others. By astronomical observations the Arabs determined the correct length of features such as the Mediterranean Sea, but after this great flowering of mapmaking, like the Chinese of about the same time, the Arabs made no significant progress, and even retrogressed.

Printed Maps of a More Detailed Globe

Meanwhile, Europe was awakening from the long period called the Middle Ages, between classical antiquity and the Renaissance. A map that expresses medieval ideas, while heralding the new era, is the T-O map from Isidore of Seville’s earlier manuscript Etymologiarum. (These letters refer to water bodies: the Mediterranean Sea and the Don and the Nile rivers forming the “T” within the “O,” or circumfluent Ocean on these largely landcovered, east-oriented world maps.) It was published in 1472 to become the first map printed in Europe (Fig. 6). Following this, the printed map gradually replaced the manuscript map for most purposes in Europe and elsewhere.

Geographia reached Italy from Byzantium c. 1410, and were translated into Latin. Soon maps were made from these instructions, and it became the business of European cartographers to improve upon this late-classical geography, as for example in the 1427 manuscript map of Scandinavia by the Dane, Claudius Clavus. Two major developments in Europe now influenced cartography, as indeed other aspects of life: the independent invention of printing in Europe, and the spread of Europeans around the globe. The (nearly) exactly repeatable representation made possible by the printing press eventually led to a wider dissemination of geographical knowledge, while the contemporaneous discovery of half of the coasts of the world and many islands, in the fifteenth and sixteenth centuries, provided new source material for European cartographers.

The first to utilize these sources and techniques were the mapmakers of the nearly land-locked states of present-day Italy and Germany: The Bologna Ptolemy, 1477, twenty-six sheets printed from engraved copper plates; and the Ulm Ptolemy, 1486, incorporating Clavus’s amendments on a single wood-cut print, are examples of this cartography. After a period of coexistence, copper-plate engraving prevailed over the wood-cut method, and the Low Countries (present Netherlands, Belgium, and the lower Rhineland) became the focus of the new global cartography. The near eclipse of woodcut printing led to the virtual abandonment of color map printing in Europe for three centuries. Copper-plate engraving does not lend itself so well to color printing as does the woodblock method, of which a few examples of colored prints from the Renaissance are extant.

With their explorations along the western shores of Africa, the Portuguese from 1420 on provided a rich source of new coastal and insular information. Likewise, the Spanish provided information about the Americas, following the discoveries by Columbus, 1492-1504, and others. Although attempts were made to keep this intelligence secret, it soon became known through the dissemination of data published mostly by the other Europeans in the form of printed maps and atlases. As indicated, the cartographers of the Low Countries eventually came to dominate this lucrative trade during the sixteenth and seventeenth centuries. Although marine charts were the first products, soon other map subjects were covered: inland provinces, urban centers especially in Europe, historical topics, biblical events, and so forth.

Several individuals and families were involved in this map and atlas production: Abraham Ortelius, Theatrum orbis terrarum (1570, and later, in several languages); Gerhard Mercator, with the map projection that bears his name (1569) and Atlas (1595); Georg Braun (Joris Bruin) and Frans Hogenberg, Civitates orbis terrarum (1572, and later); Lucas Janszoon Waghenaer, De Spieghel der Zeevaerdt (1584), translated into English as the Mariner’s Mirrour (1588); and others. There were many followers and imitators of these pioneers, and some Renaissance maps and atlases, many hand-colored prints from monotone engraved plates, became more decorative than innovative, but are prized as collector’s items to this day. The greatest cartographer of the sixteenth century was Mercator, whose projection was one of a dozen new ways of expressing the graticule (lines of latitude and longitude) invented during this period. A few of these are still in use today, including the Mercator Projection (Fig. 7), on which any straight line is a correct compass direction and thus of great value to navigators, but which has been much misused for mapping Earth distributions, where correct size is important. The English mathematician Edward Wright provided an explication and details for construction of this projection (not given by Mercator) and it was popularized by Robert Dudley and others in the seventeenth century.

Early Modern Academies and Innovative Methods of Representation

The Italian astronomer Giovanni Domenico Cassini (1625-1712) initiated another new approach to map-making when he accepted an invitation to the then recently founded Paris Observatory. Both that institution, and the observatory at Greenwich, England, were established in the middle of the seventeenth century through the sponsorship of the also newly founded Académie Royale des Sciences in France, and of the Royal Society of London, respectively. These academies were to play an important role in the development of a more scientific cartography, which characterized the mapping of the Earth during the following three centuries.

In a period of over one hundred years, four generations of the Cassini family supervised the accurate topographic mapping of France in multiple sheets. The first step was to measure the length of a degree of latitude with great accuracy, which was completed in 1670. From this base, a network of triangles was eventually extended across the whole country. The work of filling in detail, covering more than 180 sheets, was not finished until 1793. One unexpected result of this work, and measurements by French surveying expeditions at the Equator, and at high northern latitudes of Europe, was confirmation of the hypothesis of Isaac Newton that the Earth is an oblate (polar-flattened) spheroid; not a prolate spheroid, or perfect sphere, as proposed earlier. Shortly, detailed topographic surveys were undertaken in other European countries and in their overseas possessions. Thus India, under the British, became one of the best surveyed large countries at a fairly early date.

Other directions in which cartography developed in the seventeenth and eighteenth centuries include: astronomical mapping; thematic or special-subject mapping of Earth; the development of new representational techniques; and innovative map projections. The invention of the telescope led to the mapping of the Moon; Galileo’s sketch map of 1610 was the bellwether of a large number of other lunar maps (Fig. 8). Other astronomers who made contributions to this new field of mapping include: Franciscus Fontana, Johannes Hevelius, Giambattista Riccioli, and Giovanni Demonico Cassini. Through these scientists the mapping of the side of the Moon visible from Earth was improved and features named. Thematic mapping had existed before the scientific revolution of the seventeenth century, but a new cartography developed in this period, based on instrumental surveys: maps of wind directions and of magnetism by Edmond Halley; and isobathic (depth) mapping by Nicholas Cruquius are examples of the new scientific cartography (Fig. 9). Innovative methods of representation related to these developments included the isobath and the isogonic line, two of the earliest forms of the contour method, which was so greatly expanded in the following centuries that now there are some fifty types of isoline in use. The development of new and useful map projections also mark this period. A number of mathematicians were involved in the invention of different ways of representing the Earth on a grid or graticule (lines of latitude and longitude). In this regard particularly important were the equal-area projections of the German-Swiss Johann Lambert (1728-1777), arguably the most prolific inventor of map projections of all time. These advances continued as new overseas areas were “discovered” and mapped, facilitated by improved ships, and the solution of the problem of determining longitude at sea. The resolution of this age-old enigma in the late eighteenth century was owing to the invention of the marine chronometer, one of several devices that profoundly affected navigation and cartography.

Nineteenth Century: General and Thematic Mapping

The nineteenth century was a period of consolidation and diversification. Except for the polar regions, the main coastlands and islands of the world had been explored and charted at least at the reconnaissance level by 1800. However, much remained to be delineated, especially in the continental interiors (except Europe, which was reasonably well mapped by this date). Expeditions, mostly originating in Europe, were dispatched to all parts of the world in the nineteenth century, and small-scale general mapping became a large part of the activity of geographical societies that were founded at this time. Similarly in the Americas, interior areas were explored and mapped, at first in a provisional manner, but using instrumental surveys. Thus the world’s great rivers, inland seas and lakes, mountain ranges, deserts, and so forth appeared on general sheets and atlas maps, and geography became an important school, college, and university subject.

Along with this was an interest in thematic cartography, in which distributions of phenomena hitherto little known were investigated and mapped. The beginning of regular censuses in this period in many countries provided a large body of mappable data, especially on the human population. Soon demographic maps were produced, and so-called qualities of population also received attention from cartographers—disease (as in the highly informative maps of deaths by cholera in London of Dr. John Snow), crime, poverty, and so forth. Land-use maps of crops, forest cover, and urban forms soon followed, but perhaps the most remarkable development at this time was in geologic mapping.

Geologic Mapping

Great scientists turned their attention to studying the strata of the earth, as mines and canal and railroad cuts revealed the earth’s substrate. Those associated with the new science of geology included James Hutton (1726-1797) in Scotland, Abraham Gottlob Werner (1749-1817) in Germany, and Georges Cuvier (1769-1832) in France. But it was a contemporary of these natural philosophers, the English civil engineer William Smith (1769-1839), who is credited with successfully correlating fossils with associated strata. Smith used conventional colors and notations for rock types, based on age and lithology, and thus greatly advanced geological mapping (Fig. 10). So influential was Smith’s work that when a federal, general topographical mapping agency was founded in the United States (much later, in 1879), it was named the United States Geological Survey (USGS), in contrast to the earlier, military or quasi-military topographic surveys in the Old World.

A man with vision large enough to put all of the preceding geographical knowledge into a logical framework was the Prussian Alexander von Humboldt (1769-1859) in his Kosmos; his fellow Prussian, Carl Ritter (1779-1859), was a great geographical educator. Both contributed original ideas to cartography: Humboldt with continental maps and profiles, and isothermal diagrams; and Ritter with the concept of altitude tints on general relief maps (this was later formalized with conventional colors for elevation in use today).

The growing United States was the beneficiary of European expertise, as when Humboldt visited Thomas Jefferson, who (like his predecessor in the U.S. presidency, George Washington) was a surveyor and cartographer. It was through Jefferson that the rectangular method of cadastral survey was applied to the Public Domain, the most extensive example of uniform property mapping in the world. This method contrasts with irregular (metes and bounds) cadastral surveys used in the eastern United States and over most of the land area of Earth. Other Americans made signal contributions to mapping; for example, Matthew Fontaine Maury’s (1806-1873) wind and current charts greatly reduced the time taken on long voyages in the period of sailing ships. Great progress was also made in land travel through the railroad, with maps used in determining the best routes and later, when the railways were built, to assist travelers in planning trips.

The traffic-flow maps of Ireland by Henry D. Harness (1804-1883) are especially innovative contributions to transportation geography. More rapid travel in an east-west or in a west-east direction necessitated the development of uniform time zones. This was accomplished in 1884 at an International Meridian Conference held in Washington D.C., when Greenwich (England) was approved as the global Prime Meridian, and the center of the first of twenty-four (one hour) time zones, which were mapped. Lithography, which eventually led to color printing of maps, was also a nineteenth-century innovation as far as cartography was concerned.

Twentieth Century: Changing Technologies

These advances continued and accelerated in the twentieth century through such developments as the airplane and 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.

Space

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 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.