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Thursday, January 03, 2019

Geo-cells and the Mega-map

A geocell (or geo-cell), in terms of GIS and mapping, is a cell in a grid that has a resolution of 1 degree of latitude by 1 degree of longitude.  There are a total of 64,800 geocells covering a globe of the Earth. The term geocell was coined by Gene Keyes.
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 geocell is herewith defined as an area bounded by one degree of latitude and longitude. The earth-orb has 64,800 geocells. Most are quadrilaterals, but the 360 surrounding each pole are trilateral. Their length is constant; their width varies. A geocell is nearly square at the equator; narrows to a spike at the poles.
Globes and maps usually show geocells—but in combinations that vary widely from item to item: e.g., 15 x 15º, 2 x 4º, etc. Till now, so elementary a terrestrial unit as 1º x 1º has gone unnamed. And the lumping of geocells in any map has been a haphazard detail.

 A meticulous one-degree world map or globe would depict all parallels and meridians, and all 64,800 geocells (except perhaps for 1º x 5º geocells within five degrees from the poles). I have never seen or heard of an entire world map or globe drawn to one degree. The Megamap described below would be the first to incorporate all geocells.

 Most commercial globes, typically twelve inches, show 15º intervals. A few European products have 10º. Even big showpiece globes lack a full set of geocells. FDR's 50-inch globe, now in the Library of Congress, only has 5º geocells. The National Geographic Society's 11-footer in its Washington headquarters is but a blow-up of its 15º twelve-inch model.
Likewise for complete world maps: generally 15º, sometimes 10º, seldom 5º; and 1º—why bother?

There is an obvious reason why a one-degree world map or globe may heretofore have seemed impractical: the traditional division of labor between notoriously distorted world maps (or unwieldy globes), and highly precise localized charts. If you want a rough—a very rough—idea of what's where on earth, you check a world map. If you want a more exact idea about the ebb and flow of Mideast boundaries, then you examine a sectional sheet or atlas, likelier to be at the one-degree level.
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There is also a subconscious reason, so to speak, for the nonexistence of one-degree world maps and globes. A one-degree resolution in most world maps would more vividly expose their un-realism, their gross exaggerations: their abuse of geocells transformed beyond any compatibility with a globe: if there was a one-degree globe to compare them with!
Keyes, G.  1983.  Geocells and the Megamap.  Retrieved from 

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