Modern Western world maps have sustained several world views. In the seventeenth century, European geographers generally mapped the cosmographical globe, i.e., the earth as it is connected by metaphysics and geometry to the rest of the cosmos [map 1]. The double-hemisphere world maps that were then dominant were made on the same stereographic projection as star charts; their spandrels were full of cosmographical imagery and astronomical diagrams; globes were used in celestial and terrestrial pairs to model the apparent movements of the stars and the sun, respectively; the line of the ecliptic (i.e., the sun’s path from solstice to solstice) was transferred from the globes to world maps.

In the eighteenth century, as heliocentrism eroded the privileged status of cosmographical studies within education and as western European nations began to establish new empires in Asia, geographers increasingly mapped what they called the terraqueous globe, i.e., the ball of earth and water, without reference to the rest of the cosmos. In part they modified the existing convention of double-hemisphere world maps [map 2], and they also increasingly adopted Mercator’s projection—then still uncommon—for geopolitical mapping.

By the end of the eighteenth century, the terraqueous globe had become the culturally dominant conception of the world. Nineteenth-century geographers kept the double-hemisphere format and the separation of the old world from the new, but replaced the stereographic with a new, lower distortion “globular” projection; they filled the maps’ spandrels with comparative diagrams of mountain heights and river lengths, and could also add ethnographic and imperialistic imagery [map 3]. The hemispheres themselves showed mountain chains, river systems, and the division of the continents. At the same time, Mercator’s projection was used to map the political divisions of the earth, the new empires, and their maritime interconnections.