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