Maps and the Ideas they Express
MAPS AND THE IDEAS THEY EXPRESS.
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 (Fig. 1) 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 (Fig. 2). 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 (Fig. 4). 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 (Fig. 5). 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.
A new approach to mapmaking arose in Europe, building upon earlier cartographic models. Greek texts of Ptolemy's 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.
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.
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 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.
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.
See also Africa, Idea of ; America ; Europe, Idea of ; Geography ; Perspective ; Representation .
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Norman J. W. Thrower
Maps and Mapmaking
MAPS AND MAPMAKING
MAPS AND MAPMAKING. Maps are inextricably linked to how humans know the world as well as to the means by which spatial relationships can be depicted with specific tools and techniques. Thus, the history of cartography in the United States reflects human history—exploration, political change, and wars as well as technological change from designing maps on bark and vellum to creating cartographic displays with computers. The history of cartography in America is a history of making spatial knowledge visible.
Native American Maps
Any discussion of cartography in America must begin with the maps created and used by the peoples indigenous to North America. Native Americans did not have a system of writing like their European contemporaries, but they possessed meticulous methods for keeping records. These were almost entirely oral systems that depended on human memory to pass knowledge between generations. Although the first maps of America are typically considered European in origin, historians have demonstrated that these maps could have only been created with Native American assistance.
The first testament to this cartographic knowledge is documented in a story concerning an interview between the king of Portugal and Columbus in 1493. The records speak of the Native Americans who made the return trip to Europe with Columbus and who accompanied him to visit the king. The king, trying to determine just where Columbus had ventured, questioned one of the Native Americans and had him assemble a map of the Caribbean region with dried beans. The Native American cartographer expertly clustered the beans to represent Cuba and Hispaniola and used single beans to depict the smaller Bahamas and Lesser Antilles. The king asked a second Native American to do the same; he reassembled the bean map and added even more detail to the region than the first. A detailed map published in a 1511 book by Peter Martyr (in Seville) is indicative of the influence of Native American knowledge. The map depicts areas and coastlines that, at the date of publication, had yet to be traversed by Europeans. This map remains the first printed Spanish map showing any part of the Americas.
Several European cartographers noted the influence of Native American spatial knowledge on their maps. Samuel de Champlain created a map of the New England and Nova Scotia coasts in 1607. This map, now in the Library of Congress, is thought to be "one of the great cartographical treasures of America." On his survey trip near present-day Cape Ann in Massachusetts, Champlain encountered a group of Native Americans and asked them to show how the coast trended. The Native Americans took a piece of charcoal and drew a large bay, now known as Massachusetts Bay. Additionally, they drew a long river with shoals, which represented the Merrimac River. This indigenous knowledge is reflected by Champlain's beautiful chart drawn on vellum with outlines in brown ink. Captain John Smith, Virginia's first published cartographer, attributed much to native cartographers and informants.
Early Mapping of America by Europeans
Early European maps of America were often used as documents of power, denoting areas of control. Cartography at this time, however, was an inexact science and most of the early European maps of the Americas were based on relatively few explorations. Many of them depended almost entirely on Native American knowledge. Although it is thought that several maps of the New World were made before 1500, none have been authenticated. The most widely accepted "first map" of North America is known as the "Portolan World Chart" (1500, Juan de la Cosa). Many historians identify Juan de la Cosa as a Basque cartographer who accompanied Columbus on his first two voyages. Another important early map was that of Martin Waldseemüller in 1507 titled "Universalis Cosmographic." Two aspects are of note concerning this woodcut world map. First, Waldseemüller was the first to depict the land reached by Columbus as an entirely new continent, not attached in any way to Asia. Second, it is the earliest known work to label "America" as part of the New World.
At that time, most geographers continued to see the world as described by Ptolemy's (120–150 a.d.) Geographia and struggled to incorporate new knowledge of locations in the Western Hemisphere. It was not until the late 1500s that cartography began to challenge the supremacy of Ptolemy's worldview, mainly due to the greater understanding of locations in the New World. Two important atlases published in Europe reflect the changing worldview. Abraham Ortelius compiled new maps of the world based on contemporary charts and maps in his "Theatrum Orbis Terrarum" in 1570. A significant map in this collection was his "New Description of America or the New World." Fifteen years later, Gerardus Mercator's collection of 107 maps clearly signified a new view of the world invoking a new map projection that was essentially for navigation. The Wytfliet altas of 1597 was the first atlas dedicated exclusively to the Americas, with 19 copper-engraved maps.
Many of the early maps were either hand drawn or created using the Chinese technique of xylography (wood block printing), which allowed maps to be reproduced mechanically. Wood block printing was the most common method through the fifteenth century because it was relatively inexpensive. Early in the 1400s, however, calcography was invented. This method involved incising lines on a copper surface rather than carving them in wood. The engraving tool created finer lines, thereby depicting a more detailed image. This engraving process changed with the addition of a wax coating on the copper. The map was sketched lightly onto the copper through the wax and then the plate was dipped into nitric acid. The acid would not permeate the wax, but, rather, would etch the copper that had been left exposed.
Although some maps of this time were in color, most of this was done with hand tinting after the printing process. Map coloring was, for many of the period, a hobby, and manuals were produced that detailed the process. An interesting outcome of these manuals was the prescription of some "traditional" cartographic conventions such as representing political boundaries with dotted lines and symbolizing major cities with red circles.
Colonial rivalries played out cartographically in the New World. To celebrate the Dutch recapture of New Amsterdam (New York) from the English in 1673, Hugo Allard created the "New and Exact Map of All New Netherland." Other colonial period maps were used to depict the extent of control in North America, such as Guillaume Delisle's "Carte de la Lousiiane et du Cours du Mississipi" (1718), which showed the Mississippi Valley and delta region as possessions of France totally surrounded by British settlement. Another example is William Popple's (1733) twenty-sheet "Map of the British Empire in America with the French and Spanish Settlements adjacent thereto," which reflected the extent of known North America and the degree to which Britain controlled it.
The year 1755 is known as a year of great maps. Considered the most notable map of this year was John Mitchell's "A Map of the British and French Dominions in North America with the Roads, Distances, Limits, and Extent of the Settlements." Essentially, this map served as a rebuttal to French boundary claims in the New World. The information used to create the map was as sophisticated as possible for the day, with latitude determined with the quadrant and longitude remaining slightly less precise. This map was taken to the Treaty of Paris in 1783 and was used well into the twentieth century to resolve boundary disputes. Because of its accuracy in depiction of locations and its completeness, it is often noted by cartographic historians as the most important map in the history of American cartography.
Mapping the New Nation
The first map compiled, engraved, and completed by an American was Abel Buell's (1784) "A New and Correct Map of the United States of North America Layd down from the latest Observations and best Authority agreeable to the Peace of 1783." This map, in many ways, represents the end of an era. By the early 1800s, cartography had begun to move from works of art based on geographic knowledge to works of science based on known geographic fact. Earlier maps, often incorrect, were no longer tolerated; too many people had knowledge of the world. Beginning in the early 1800s, maps became quite similar in appearance, often seen as a triumph of science over art.
Cartography During the Nineteenth Century
By 1800, several atlases of the new nation had already been created (The American Pilot, 1792, and Casey's American Atlas, 1795). However, the publication of Henry Schenk Tanner's New American Atlas (1823) indicated a change in cartography now based on rigorous scientific surveying. Surveyors used distinct color and uniform symbology, indicated cultural features, and retained the "received" names of places. This atlas marks the first comprehensive analytical compilation of American cartographic data, and maps of each state were of a uniform size and scale.
There are several notable maps in the history of American cartography in the first half of the nineteenth century. William Maclure's 1809 map, considered by many as the origin of thematic cartography, depicts the known geology of the United States imprinted over a topographic map. Exploration maps such as "Lewis and Clark's Track Across the Western Portion of North America…" (1814) greatly enhanced knowledge of the continent. The earliest American publication of an ethnographic map was Albert Gallatin's (1836) representation of Native Americans classified by linguistic family. Elias Loomis's maps, many designed during the 1840s, are considered to be the earliest maps based entirely on scientific data. Considered the origin of weather maps, most of these depict meteorological phenomena.
Between 1814 and 1830, a revolution occurred in the printing of maps. Lithography was a new printing technology that was based on the chemical repellence of oil and water. Instead of an image being cut into a plate, maps were drawn with greasy ink or crayons on a specially prepared stone. The stone was then moistened with water (repelled in the areas with greasy ink) and the printing ink was rolled onto the stone, adhering to only the mapped (inked) areas. The map was then made by pressing the paper against the inked drawing. Lithography significantly lowered the cost and increased the speed of map production. A few years later, wax engraving (cerography) began to have a large influence on American cartography. The map image was engraved on wax rather than on copper or stone. This image was then used to create a mold on a thin metal plate that could be used on a letterpress printing machine. With this method, type could be inserted in the wax mold rather than engraving each letter by hand. These two new printing processes, along with the lower cost of wood pulp paper and a shift in production from individual maps to maps published in sets based on systematic surveying and mapping, dramatically increased the number and use of maps in the United States.
During the second half of the 1800s, maps were designed for development, population statistics, war, ownership, health, westward expansion, and protection of property. County maps were commercially produced to show land ownership by 1850. Notable and widely used maps were those of the Sanborn Map and Publishing Company (begun in 1865). These large-scale maps depicted the locations and dimensions of buildings and included the structural materials of each in order for insurance companies to determine fire risk. General Land Office Maps standardized the format and content of maps. During the Civil War (1861–1865), map accuracy was critical. Many of the topographic maps of the southeastern United States made during the war were used well into the twentieth century because of their high level of accuracy. A uniquely American cartographic form emerged after the Civil War. Panoramic views of U.S. cities using an oblique perspective became a common and popular map form that lasted into the early twentieth century. A map representing the distribution of slave population in 1860 is often noted as the first map of census data in the United States. Rand McNally, a small commercial printing firm at the time, found that their addition of small strip maps to accompany their railroad guide became enormously popular. By 1874, the First Statistical Atlas of the United States was published. This prompted an increase in thematic and statistical maps that incorporated more diverse political and social data. By this time, physicians began using cartographical-statistical methods to document diffusion and distribution of major epidemics of tuberculosis, pneumonia, malaria, and typhoid fever. By 1879, the U.S. Geological Survey (USGS) had mapped the entire nation by quadrilateral tracts. The initial scale of these maps was 1:250,000. The USGS maps used standardized symbology, colors, and place names. The simplified cartographic design made the maps accessible to the general public.
Published at the turn of the century (1898), The Statistical Atlas of the United States Based on the Results of the Eleventh Census represents the most comprehensive and analytical cartography in the United States to date. This atlas incorporated four main thematic mapping methods that were devised during the nineteenth century: dot maps (uniform symbols represent a quantity), choropleth maps (different shadings represent different values in different areas), flow lines (indicate direction and amount of a flow), and graduated symbols (varying sizes of symbols represent different values).
A significant change in transportation from rail to automobiles in the early part of the twentieth century influenced the demand for practical and accurate road maps and prompted a boom in commercial cartography. In the academic world, the Hart American History Series of maps (1918–1921) reflected the influence of James Harvey Robinson's emphasis on "totality" in historical study in his New History (1916). Additionally, a significant volume, C. O. Paulin's Atlas of the Historical Geography of the United States, compiled more than 600 maps documenting American history.
Scientific mapping techniques were well established by the beginning of the twentieth century. A national inventory of soils by county was undertaken by the U.S. Department of agriculture in order to assist American farmers. By 1940, there were well over 1,500 maps just depicting different aspects of soils in the United States. This type of survey was a common "New Deal" government practice during which time there was an enormous expansion in maps of the United States, representing statistics such as population, manufacturing, climate, agriculture, and urban housing conditions.
Many changes in cartographic techniques evolved during the twentieth century. Representing the earth's third dimension had always been a cartographic challenge. Erwin Raisz's "Physiographic Provinces of North America" was published in 1939, and demonstrated a realistic depiction of relief through numerous physiographic symbols that he developed. Aerial photography, a technique employed in both world wars of the twentieth century, influenced mapping dramatically by allowing cartographers to view the earth from a planar perspective (the perspective of most maps) for the first time. Three-dimensional terrain models and negative scribing both had their roots in war as well and contributed to advances in cartographic techniques in midcentury.
However, it is the period from 1950 to 1990 that is classified as revolutionary in cartography, with numerous innovations and developments for representing spatial relationships. During the 1950s, air photos and maps were merged to create what is now known as orthophoto maps. On these maps, traditional map symbols are placed on rectified air photos. In the early 1960s, Howard Fisher, a Harvard sociologist, developed a mapping technique known as SYMAP that used an early computer to create maps depicting density data. Computer cartographic techniques made mapping quicker and more accurate. Data sources such as rectified air photos, satellite images (early 1970s), and digital databases all helped to usher in a new period in cartography in the United States. Mapping software based on Geographic Information Systems (GIS) created a system in which spatial data and attribute data could be linked. This new method of managing spatial data permitted numerous different maps to be created for just one specific purpose rather than as a general map meeting many needs. By the end of the twentieth century, people could access data and mapping software via the Internet to create a map of nearly any place and show any available statistical relationship. Additionally, virtual maps have allowed cartographers to show temporal relationships, how places have changed over time. No longer do maps show a frozen moment in time. By using animation techniques, cartography is reaching into new areas of research called cartographic visualization. The National Atlas of the United States exemplifies the rapid change in cartography during the last thirty years of the twentieth century. Initially a huge volume of 765 maps representing the history of cartography in America (1970), by 2001 it was available online with an infinite number of maps available to each individual user.
Cartography has experienced dramatic change in methodology and presentation from the Columbian encounter to present day. Once created as ornate works of art by specially trained individuals, maps by the end of the twentieth century could be created by anyone with access to data and mapping software. Maps, however, remain representations of reality. Maps represent how individuals see and interpret the world, whether they are maps from the 1500s on vellum or those that animate on a computer screen.
De Vorsey, Louis Jr. "Silent Witnesses: Native American Maps." Georgia Review (1992): 709–726.
Portinaro, Pierluigi, and Franco Knirsch. The Cartography ofNorth America, 1500–1800. New York: Facts on File, 1987.
Schwartz, Seymour I., and Ralph E. Ehrenberg. The Mapping ofAmerica. New York: H. N. Abrams, 1980.
Thrower, Norman J. W. Maps and Civilization: Cartography inCulture and Society. 2d ed. Chicago: University of Chicago Press, 1999.
Tooley, R. V., and Charles Bricker. Landmarks of Mapmaking. Ware, Hertfordshire, U.K.: Wordsworth Press, 1989.
Maps and Mapmaking
Maps and Mapmaking
Maps have been made for thousands of years as a means to convey information about the surface of the Earth. Some maps are highly complex, organized data sets that have been assembled by cartographers , mathematicians, or geographers who wish to illustrate the lay of the land. Maps are able to provide tremendous amounts of information on a two-dimensional surface.
The History of Mapmaking
The first attempt to establish a grid system on Earth was in 150 c.e. by the Greek astronomer Ptolemy. He established the concept of imaginary lines that intersected at regular intervals, making it possible to locate a particular position from reference points on a grid.
Using information from his astronomical predecessors, Ptolemy established latitude as imaginary parallel lines, equally spaced, that circled the world in a horizontal plane. The zero degree parallel was the equator. He chose this parallel as zero because it has the largest diameter of any latitude.
Ptolemy proposed the concept of longitude , equally spaced imaginary lines that run north and south, as a way of dividing Earth into a set of lines that are parallel to one another at the equator. The zero meridian was originally chosen arbitrarily by Ptolemy. Throughout the centuries, the Prime Meridian has been changed as a result of various political interests. Through an international consensus, it was agreed that the prime meridian would pass through Greenwich, England, going from the North to the South Poles.
Mathematics in Maps
One of the first mathematical calculations to be determined for a map is the scale. Because it is usually infeasible to make a life-sized map, mapmakers must reduce the size of real objects and distances proportionally. The smaller a map scale, the more detail the maker can include.
Projections are one of the most difficult tasks of mapmaking. A projection is an attempt to draw the gridlines of a spherical object on a flat surface. In reality, it is impossible to draw the true gridlines of Earth on a flat surface without losing some of the mathematical accuracy of distance or area. For example, on a flat map, Greenland appears much larger in proportion to areas that are closer to the equator than it is in reality.
Most projections are derived from geometric figures. To make geometric maps, trigonometry is used to solve the problems of distortion.
Gerardus Mercator was one of the first people to solve the problem of distortion in maps. In 1569 he drew his map so that the meridians remained vertical and equally spaced while the parallels increased in spacing as they approached the equator. Mercator determined the correct degree of increase between parallels from the secant of the latitude.
Cylindrical maps represent Earth as a cylinder on which the parallels are horizontal lines and the meridians are perfectly vertical. These maps may seem impractical because of the tremendous distortion in the polar latitudes, but they are excellent for use with compass bearing, which can be plotted as straight lines.
Conic projections are maps drawn as a projection from a point above the North or South Poles. The map intersects Earth at a point tangent to a specific point on the sphere, usually a pre-selected parallel. Polyconic projections are used in large-scale map series. Each conic section is made to correspond to a particular latitude.
Azimuthal projections are maps made from viewing Earth from a particular perspective; either outer space, the interior of Earth, or different
hemispheres of Earth. The map itself is a flattened disk with its center at a point tangent to a reference point. The map represents a view from one of the specific points mentioned. These types of maps are most often seen as polar projections in which the polar land and sea are shown together as a circle.
Maps are often updated using aerial photographs. These photographs are known as digital orthophoto quadrangles (DOQ). DOQs are altered so that they have the geometric properties of a map. There are four elements necessary in an aerial photograph: three identifiable ground positions, camera calibration specifications, a digital elevation model of the area in the photograph, and a high-resolution digital image of the photograph. The picture is then processed pixel by pixel to create an image with true geographic positions.
Geographers, mathematicians, and computer analysts, among others, continue to improve the quality and reliability of maps. Modern digital technology has helped enhance our current understanding of the surface of Earth. Mapmaking will continue to become more refined as technology continues to improve.
see also Cartographer; Geography; Global Positioning System.
Brook E. Hall
Brown, Lloyd A. Map Making: The Art that Became a Science. Boston: Little, Brown, 1960.
Goss, John. The Mapping of North America: Three Centuries of Map-Making, 1500–1860. Secaucus, NY: Wellfleet Press, 1990.
Menno-Jan Kraak, and Allan Brown. Web Cartography: Developments and Prospects. New York: Taylor and Francis, 2000.
Robinson, Arthur, et al. Elements of Cartography, 6th ed. New York: John Wiley, 1995.
Digital Backyard. USGS TerraServer. <http://mapping.usgs.gov/digitalbackyard/>.
Roman Britain did not make use of maps. The early Roman conquerors must have relied upon native guides and interpreters. Once a road system had been developed, they used itineraries, numbering the routes and setting up milestones. The Antonine Itinerary of the Empire in the 4th cent. showed fifteen roads in Britain, and more than 100 place-names, with distances. Ptolemy's 2nd-cent. map showed the British Isles. Their juxtaposition to the mainland of Gaul was plausible, but Hibernia was too small, and northern Scotland tilted over to the north-east. Even if available it would have been no use to travellers or messengers.
Medieval map-makers began to fill in some detail. The Mappa Mundi (c.1280), now in Hereford cathedral, was as much theological as geographical, and centred on Jerusalem: Scotland was shown as an island and Ireland was divided by the Boyne. A much better map had been produced some 30 years before by Matthew Paris, showing recognizable details like the Cornish peninsula and East Anglia: it had no roads and some rather strange rivers. A century later came the Gough map (named after the 18th-cent. collector Richard Gough and now in the Bodleian), perhaps an official road map, good on England and with distances shown. By the Tudor period engraved maps of some accuracy were being produced, though Ireland and northern Scotland continued to give trouble. Mercator in 1564 offered a map of the British Isles, with information passed on by Lawrence Nowell, dean of Lichfield, perhaps through John Dee. Elizabeth's government in the 1570s gave assistance to Christopher Saxton, and in James I's reign John Speed produced famous maps, including the Realm of the Empire of Great Britaine (1611–12). Itineraries or strip-maps were still much in use for travellers and an important series was produced by John Ogilby in 1675.
By the 18th cent. county maps (some sponsored by the Royal Society of Arts), estate maps, and town maps were becoming common, as well as oceanic charts and harbour maps. Technological advances included a marked wheel for measuring distances accurately, a greatly improved theodolite, and the gradual elimination of picturesque but irrelevant detail. The Jacobite rebellion of 1745 gave an unexpected boost to map-making, since the absence of reliable maps of northern Scotland had proved an obstacle to the work of ‘pacification’. The Ordnance Survey began by surveying Scotland and then turned its attention elsewhere, producing from 1801 onwards a series of excellent county maps.
In the 19th cent. large-scale maps were produced, and cartographers turned to surveying colonial territories. In Britain, pocket-sized itineraries were being printed deep into the 20th cent., but with the vast increase in motor travel, particularly after 1945, road atlases became the best sellers, complete with distance charts, town maps, places of interest, and detailed indexes.
J. A. Cannon
See also 178. GEOGRAPHY ;352. REPRESENTATION ;399. TRAVEL .
- the process of mapmaking by means of aerial survey.
- the production of maps, including construction of projections, design, compilation, drafting, and reproduction. Also chartography, chartology. —cartographer , n. —cartographic , adj.
- 1. a description, map, or chart of a particular region or area.
- 2. the art of preparing such descriptions or maps. —chorographer , n. —chorographic , adj.
- a rhumb line or curve on the surface of a sphere intersecting all meridians at the same angle; hence, the course of a ship or aircraft following a constant compass direction. —loxodromic , adj.
- the use of photography for surveying or map-making.
- surveying or map-making by means of photography. —phototopographic, phototopographical , adj.
- a map showing half or more of the sphere of the heavens, indicating which part is visible at what hour from a given location. —planispheric, planispherical , adj.
- 1. the detailed mapping or description of the features of a relatively small area, district, or locality.
- 2. the relief features or surface configuration of an area. —topographer , n. —topographic , adj.