Friday, May 21, 2010

CARTOGRAPHY Part IV


De Bry’s Map of the New World. This early map of North and South America was rendered in 1596 by the Flemish engraver Theodor de Bry (ca. 1527–1598).

But as cartography catered to the needs of early modern society, with its specializations reflecting this, the mapping of the world went on at very different paces. The search for El Dorado and the Northwest Passage were reflected in an intense cartographic interest in these regions of the globe, whereas others waned. Desert regions were ignored, so that Sir Walter Raleigh (1554–1618), believing in and searching for a suitably empty spot on the map where to locate the terrestrial paradise, chose Mesopotamia. Although the external shape of the African continent was, as has been discussed, largely resolved by Bartholomeu Dias and subsequent Portuguese voyages at the end of the fifteenth century, the African interior remained very much a blank space until the late eighteenth century, and cosmographers were forced to fall back on classical schemes as an aid, for example, in resolving questions such as the true sources of the Nile. It is probably for this reason that mythical constructs such as the Kingdom of Prester John were so slow to disappear from European maps as, for example, we find from Abraham Ortelius’s (1527–1598) map of 1573. The vast spaces of the Pacific, as understood from Ferdinand Magellan’s (1480–1521) epic circumnavigation of the world (1519–1521), were also only gradually revealed in the second half of the eighteenth century and, as historians like Alan Frost have pointed out, functioned as a second New World at the time of the European Enlightenment.

The next great cartographic leap is the work of the Flemish geographer Gerhardus Mercator (1512–1594), who tried in 1568 to solve a very practical problem, that of representing the globe as a flat surface on which courses could be logged and plotted. Basically he turned the globe into a cylinder. Cut down one side and unrolled, this produced a grid of lines of longitude and latitude that would always tell you where you were with reference to the poles. What it could not do was provide accurate comparisons of surface area because, of course, the ends of the cylinders are lines; the poles, though, should be points. Mercator’s picture of the world therefore becomes very distorted as one sails a long way away from the equator. Although not universally approved, Mercator’s projection provided a good scientific basis for the calculation of position and direction on the high seas. Subsequent work, such as Edward Wright’s (1561–1615) correction for magnetic variations in the North Sea, was able to build on Mercator’s legacy rather than require an entirely new platform.

Other problems remained for later generations to resolve. The inability to calculate longitude accurately, for example, which resulted in the east-west extensions of the Mediterranean and of North and South America, was initially approached nationally through the establishment of meridian lines running through the national observatory (founded in London 1675; Paris in 1699). This functioned as a basis for the first large-scale general maps of the nation. But as a more widely international and theoretical problem, the solution, as Dava Sobel has shown, was hit upon by five revolutionary timekeepers constructed between 1730 and 1770 by Yorkshireman John Harrison (1693–1776) in his single-minded pursuit of the £20,000 longitude prize offered by parliament.

While mapmakers struggled with the mathematical challenges of depicting the world in two dimensions, a number of scientific steps forward were made in the task of gathering information about the shape of the earth at a local level and transforming that information onto local maps, and then by way of coordinates on to a continuous projection. The mathematician Gemma Frisius (1508–1555) explained the construction of surveying techniques by means of triangulation in 1533, and what followed was a rapid rise in triangulated surveys serving primarily the practical task of defining boundaries, lines of property, and military fortifications, and from which certain conventions of descriptive geography emerged as well as a technical discussion as to the measuring and depiction of land in small scale. These were known as chorographic maps, and the discipline as chorography.

It is, however, one of the paradoxes of the Renaissance that it was not principally a scientific movement. Even the Ptolemaic revival was more of a literary event, a rediscovery of classical theory, whose content, as we have seen, was ultimately irrelevant to the fifteenth century. The most popular works on geography of the age, such as Sebastian Münster’s (1489–1552) Cosmographia of 1544, were still essentially traditional topographic catalogues, rich with cultural features such as costumes and illustrations, and, as the French historian Frank Lestringeant has shown, by the end of the Renaissance was a genre in crisis. In cosmology, the classical, geometric model of the heavens with its interlocking spheres was still dominant. The experiment and discovery that were taking place in the projections of the maps, on the other hand, and the treatises from 1590 that dealt with this theme hardly mirrored the conservative world of the seafarers. Seafarers stuck to their unscientific plane-chart model, which was not built on a mathematical projection at all, but simply divided space evenly into squares or rectangles of one latitude degree by one longitude degree. In effect, these charts ignored the fact that the earth was a sphere.

In conclusion, the cartographic revolution of the Renaissance was a revolution that only went so far. Experience and reason were values and approaches much trumpeted, but did not completely outweigh inherited authority as a source of knowledge. Iconoclastic refusals to sanction the past that we find in the French cosmographer André Thevet, for example, were isolated voices. Secularization of the map as an object had certainly occurred and determined both its new form and its new social context. But even mathematicians like Mercator consciously presented traditional geographical thought and legend alongside the recent discoveries of his contemporaries.

BIBLIOGRAPHY Brown, L.A. The Story of Maps. New York: Dover Publications, 1979. Buisseret, David, ed. Monarchs, Ministers, and Maps: the Emergence of Cartography as a Tool of Government in Early Modern Europe. Chicago: University of Chicago Press, 1992. Buisseret, Davis. The Mapmaker’s Quest: Depicting New Worlds in Renaissance Europe. Oxford: Oxford University Press, 2003. Fernández-Armesto, Felipe. Before Columbus: Exploration and Colonisation from the Mediterranean to the Atlantic, 1229–1492. Basingstoke, England: Macmillan Education, 1987. Lestringeant, Frank. Andre´ Thevet. Cosmographe des derniers Valois. Genève: Droz, 1991. Sobel, Dava. The Illustrated Longitude. New York: Walker, 1998. Whitfield, Peter. The Image of the World. Twenty Centuries of World Maps. San Francisco: Pomegranate Artbooks, 1994.

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