Medieval maps of the world, save the most schematic, had contained geographical information but this was a subsidiary to a symbolic intent; to remind the viewer that God had created a world represented by a circle of lands whose center was His own chosen Jerusalem. But from the early sixteenth century, thanks to a new mathematical interest in cartographical projections that could take account of the curvature of the earth, more accurate assessments of degrees of latitude, and to the challenge of ever-expanding knowledge of the world’s surface, the cartography of Europe began to enable Europeans to imagine, believably the geographical space in which they lived.
Cartography in the sixteenth century became, indeed, almost a craze. The number of professional surveyor-mapmakers grew and was joined by amateurs fired by an interest in recording topographical facts in a graphic form recognizable to and usable by others. Statesman used them for strategic purposes. Monarchs commissioned them as symbols of power. All over Europe they became part of the mental furniture of educated men.
The printing press offered a widening audience. A heightened prosperity increased the interest of the bustle and the allure of descriptions of cities, and made the contrasts between them and the diurnal tasks of the countryside more intriguing. The new cartography gave the writer’s eye a brighter focus. A more coherent sense of patriotism played its part. And patriotism was closely connected with the cult of classical antiquity which encouraged writers to dig through their recent and medieval past to reveal that their country, too, had been part of Rome’s magnificent outreach. Maps were at first printed using carved wooden blocks (see above). Among the most important map makers of this period was Sebastian Münster in Basel (now Switzerland). His Geographia, published in 1540, became the new global standard for maps of the world. Gerardus Mercator of Flanders (Belgium) was the leading cartographer of the mid-16th century. He developed a cylindrical projection that is still widely used for navigation charts and global maps. He published a map of the world in 1569 based on this projection. Many other map projections were soon developed.
The compilers of maps in atlases accepted the conventions used by the cartographers with whom they corresponded, some of whom, used dotted lines to indicate countries or their equivalent administrative areas. The revised versions Abraham Ortelius (Theatrum Orbis Terrarum, Antwerp) published after 1570 included more of these lines as the convention became more widely established, but they were more commonly used to indicate regional than political units.
[Hale, John, The Civilization of Europe in the Renaissance., pp. 15-35.]