Cartographers and Geographers

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Cartographers and Geographers

Stagnant Field of Study. Geography had no independent status as a field of study in the early Renaissance. Geographical analysis did occur in travel literature, in works of nonfiction that purported to be universal histories, and in maps. The travel literature, such as accounts of Marco Polo or Sir John Mandeville, lacked precise distances and frequently incorporated purely fictional material. The universal histories were largely based on the accounts of the travel literature and thus further distorted reality. Moreover, the travel literature of the late fifteenth century was basically the same, especially in terms of accuracy, as that of the thirteenth century. During the fifteenth century Europeans sailed to the Americas and India, but little new appeared in the way of geographical studies. Printers well into the early sixteenth century preferred to republish these older and geographically incorrect accounts rather than take the financial risk of assimilating the current information into a new genre.

Revival. Mapmakers, also known as cartographers, were more interested in appeasing the political ambitions of their noble patrons than in achieving objectivity and accuracy. European maps in the Renaissance were usually meant for public display in churches and civic buildings. These “world maps” were essentially useless, and thus most travelers found their way by asking directions at each settlement they encountered. However, late in the sixteenth century European geographers and cartographers created accurate maps that displayed a clear understanding of modern geography. The origins of this change can be traced to the early humanists, whose interest in ancient geographers and Greek learning contributed to a revival of works written by classical geographers such as Claudius Ptolemy and Strabo. As late as 1550, world maps were of no value to mariners and navigational maps grossly distorted the world. By the end of the century the mathematical methods of both Ptolemy and the Italian military engineers allowed mapmakers to merge the previously distinct world and navigational maps. Gerardus Mercator and Abraham Ortelius combined these traditions into maps that the modern reader would readily recognize. World geography was thus born a century after Christopher Columbus and Bartholomeu Dias made their historic voyages.

T-O World Maps. World maps prior to the sixteenth century were schematic representations of the world. Most were based on Isidore of Seville's “T-O” map, although some were zone maps known as Macrobian maps. Despite being called mappae mundi (world maps), the T-O maps followed the classical division of the habitable world into the three continents of Asia, Africa, and Europe. The name T-O derives from the location of the continents on a flat circular map. The “O” is the ocean that encircles the three continents, and the “T” is a water line that divides the continents. The stem of the “T” is the Mediterranean Sea that separates Europe on the left from Africa on the right. The cross of the “T” represents the Nile

and Don rivers that separate Africa and Europe respectively from Asia. T-O maps grotesquely distorted reality, but they served an ecclesiastical function by supporting Christian ideas such as the biblical account that lands had been distributed to the sons of Noah. Jerusalem appears at the center of the ecclesiastically based T-O world maps.

Portolan Charts. By 1350 the magnetic compass was a common tool of European navigators. The compass transformed sailors' portolani (notebooks) into charts with traverse tables that explained distances of daily travel. Portolan charts allowed sailors to use their knowledge of the Mediterranean coasts and islands for a method of sailing known as “plain sailing,” whereby navigators followed straight, or rhumb lines. These straight rhumb lines intersected each other and ran to key ports. The system worked well in the Mediterranean, where coastal markings were easily recognizable, but portolan charts did not allow for the fact that the earth is not flat. A curved surface cannot be mapped on a flat plane without a system of projection. Only slight latitudinal variations exist in the Mediterranean and shorelines were nearby, but Portuguese sailors who were sailing south along the coast of Africa crossed a wide latitudinal range. Moreover, the African coast has fewer islands and more dangerous winds than the Mediterranean. A navigational error on the Mediterranean Sea might send a boat to the wrong shore, whereas the same error for the Portuguese in the Atlantic could send the boat clear across the ocean. Portuguese sailors were thus forced to forsake straight-line sailing and to seek other ways to determine latitude.

Forgotten Solution. Ptolemy had actually solved the problem of representing a spherical section of the earth's surface on a flat map more than one thousand years before the Renaissance. A Greek manuscript of Ptolemy's Geography was brought to Florence in 1406 and translated into Latin in 1410. Ptolemy introduced a difference in scale and a clear difference between unmeasured works, such as the mappae mundi, and maps based on coordinates. Ptolemy's use of coordinates was slowly assimilated into European mapmaking, and in the 1460s many maps of northern Europe were added to Ptolemy's book. The first printed edition of Geography appeared in 1475, complete with new maps. The coordinates of latitude and longitude were frequently incorrect in early editions of the book, but the work stimulated the pursuit of better ways to represent the earth's curvature.

Cosmography. Ptolemy's mapping of the entire world on a framework of celestially derived circles became the standard model until Dias circumnavigated the Cape of Good Hope (1488), Columbus voyaged to the Americas (1492), and Ferdinand Magellan circumnavigated the globe (1519-1522). The Ptolemaic map evolved into an oval map that depicted the whole spherical globe on a flat surface. World maps in the sixteenth century became known as cosmographia. The oval world projection replaced the ecclesiastically determined mappae mundi. The basic textbook for cartogrpahers in the sixteenth century was Peter Apian's Cosmographia (1533). Apian's work relied heavily on Ptolemy's Geographia but with a new addition drawn from the mathematics of military engineers. Military and civil engineers of the Renaissance became interested in scaled representations that were mathematically precise. They developed mathematical methodology using scales and projections. Their techniques influenced Apian, who explained in his volume how triangulation could be used to accurately create land maps.

Gerardus Mercator. Maps of navigation and the world cosmographia were two distinct types of maps until Mercator merged them in his famous 1569 projection map. A former land surveyor, Mercator employed a projection that incorporated the cosmographical grid that allowed the globe's surface to be projected onto a flat surface while simultaneously allowing compass courses to be plotted with a straight edge. The Mercator projector was further refined by Edward Wright in 1599, and the Wright-Mercator projection became the basis for navigation until the twentieth century.

Politics of Mapmaking. Despite the technological advances of Mercator's world map, the map itself has a distinctive pro-Spanish bent. Mercator was employed by the king of Spain when the Spanish and Portuguese crowns essentially divided the two hemispheres. The Spanish Western Hemisphere, the Americas, is in the top left of the map in a manner that overstates the significance and size of the Spanish area. Cartography in the sixteenth century was a way to advertise, be it the Church advertising the centrality of Jerusalem and Christianity in the T-O maps or the cartographers in the pay of the Spanish throne, who advertised the promise of Spanish domains. Noble patronage of maps decreased dramatically after Mercator's map because shipping fell into the hands of commercial companies. These shipping companies wanted maps that were accurate and reliable to ensure that vessels and investments were not lost. By 1600, cartographers owed their allegiance to Dutch and English joint-stock companies and not to the royal families of Europe.

PRESTER JOHN

The author of The Travels of Sir John Mandeville remains unknown but many scholars believe it was written by an exiled Irish physician living in France, It circulated around Europe in the late fourteenth century and includes several adventurous and outlandish stories. The stories are now known to be hoaxes, but they nonetheless serve as a mirror to the medieval mind. The legendary story of Prester John, about an all-powerful ruler who receives the rite of baptism and ordination, appears first in the chronicle of Otto of Freising in 1145, but probably originated during the expansion of Christianity many years earlier. The validity of the story was still being seriously debated as late as 1646 and the Nuremberg globe of Renaissance geographer Martin Behaim includes Mandeville's magnetic rocks between Java Major and the mainland of India.

This emperor, Prester John, holds full great land, and hath many full noble cities and good towns in his realm, and many great diverse isles and large. For all the country of Ind is devised in isles for the great floods that come from Paradise, that depart all the land in many parts. And also in the sea he hath full many isles. And the best city in the Isle of Pentexoire is Nyse ....

This Prester John hath under him many kinds and many isles and many diverse folk of diverse conditions. And this land is full good and rich, but not so rich as is the land of the great Chan. For the merchants come not thither so commonly for to buy merchandises, as they do in the land of the great Chan, for it is too far to travel to. And on that other part, in the Isle of Cathay, men find all manner of thing that is need to man—cloths of gold, of silk, of spkery and all manner avoirdupois. And therefore, albeit that men have greater cheap in the Isle of Prester John . . . men dread the long way and the great perils in the sea in those parts....

In the land of Prester John be many diverse things and many precious stones, so great and so large, that men make of them vessels, as platters, dishes and cups. And many other marvels be there, that it were too cumbrous and too long to put it in scripture of books; but of the principal isles and of his estate and of his law, I shall tell you some part.

This Emperor Prester John is Christian, and a great part of his country also. But yet, they have not all the articles of our faith as we have. They believe well in the Father, in the Son, and in the Holy Ghost. And they be full devout and right true one to another.

Source: The Travels of SirJohn Mandeville (New York: Dover, 1964) pp. 178-179.