The center of the map

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The other day I was listening to one of Thomas Laqueur's History 5 lectures and he mentioned that many older maps were centered on Jerusalem [*]. Laqueur observes that the center of a map is arbitrary and that there's nothing wrong with using Jerusalem as the center. Well, sort of. It's true that the Earth is roughly a sphere, but remember that it spins on an axis going between the North and South poles which gives it a natural asymmetry. So, while the longitude of the center of a map is certainly arbitrary and there's nothing particularly special about Greenwich1, the Equator is special and it would be sort of weird to center the map vertically anywhere else—and at about 31 degrees North, Jerusalem is way off the Equator.

Note that this isn't purely a matter of latitude not having been discovered yet. The Greeks knew that the Earth was a sphere and already had the idea of latitude and longitude. Techniques for measuring latitude (and impractical techniques for measuring longitude) were known in Medieval Europe as well at the time such maps were produced. The choice of the center of the map was an issue of religious commitments, not simple ignorance.

1. See Einstein's Clocks, Poincare's Maps: Empires of Time for a lucid description of the political maneuvering around the selection of GMT as the zero reference for time.

1 Comments

I've been trying for some time to find a globe oriented with Antarctica at the top. I could do this with a regular globe, but the writing would be upside-down.

I presume demand isn't great enough for anyone to manufacture such a globe. You can find maps with south-at-top orientation, mostly from Australia, but no globes.

I want to have such a globe to put it in my office. For me it serves as a reminder that many things we naturally think of as immutable are in fact completely arbitrary.

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