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I've seen lots of world maps in the shape of two disks that touch, each one a separate projection of one hemisphere onto a disk -- usually the Western Hemisphere and the Eastern Hemisphere -- so together the full map covers the entire globe.

Is there a standard name for this kind of map projection onto 2 circular disks?

enter image description here from Wikipedia: Rumold Mercator

enter image description here from Wikipedia commons

Ideally I'd like a general name for all "2-disk" arrangements like this, but I'd be happy with separate specific names for "2 disks that use a Wulff net" and "2 disks that use a Schmidt net" and "2 disks that use a Mollweide map".

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Nonperspective Azimuthal Projections… – Mapperz Jan 22 '13 at 21:52
Any projection of the sphere that maps a hemisphere into a disk can be made to work like this simply by mapping two complementary hemispheres and placing those maps side-to-side. Among such projections are the orthographic, stereographic, gnomonic, and azimuthal equidistant. Most azimuthal projections will map a hemisphere onto a disk. Perhaps that's why there is not a generic name for such two-disk maps AFAIK. – whuber Jan 22 '13 at 23:14
up vote 5 down vote accepted

A double hemisphere projection. Here's another example from 1691:

enter image description here

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That's a nice illustration. However, the question does not ask for a specific name, but for a "general" name for all such world maps. – whuber Jan 22 '13 at 23:15
@whuber Post edited to address comments. A "Double Hemisphere" projection is about as general as it gets--and according to the cartographer of the posted map, pretty accurate (i.e. Deux Plans-Hemispheres"). – Aaron Jan 23 '13 at 0:02

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