Geography Reference
In-Depth Information
Earth's rotation causes its oblate-ness. The speed of Earth's rotation is much faster at
the Equator than near the Poles. This difference in speed may not be obvious, so think
of it this way. Earth's circumference measured along the Equator is about 25,000 miles.
If you stand at a spot on the Equator for one day — for one full rotation — you'll travel
25,000 miles. In contrast, if you stand a foot or two from the North Pole for one rotation,
you'll only travel a few yards. Obviously, somebody who travels 25,000 miles in one day
is moving much faster than somebody who travels a few yards in the same time. So, the
area near the Equator is spinning much faster than other parts of Earth. The outward, or
centrifugal,
force the high speed of rotation causes is so great that Earth bulges around
the Equator as a result.
Realizing Exactly How Flat Maps Lie
The business of making map projections requires a somewhat deviant personality. Cartographers
know that maps that lie flat lie. They know for certain before they begin a project that it's absolutely
impossible to create a flat map that looks exactly like the world. Does that deter them? Nope. No way.
Cartographers have developed literally dozens of different kinds of map projections over the years.
Each one contains some degree of misinformation. If you're like most people you've given little or
no thought to map projections nor have you suffered from not doing so. Or have you?
Understanding the facts about maps can't help but make you a better-informed person. Maps are
a common means of communicating information. They pop up in newspaper articles, magazines,
topics, TV programs, and elsewhere. Because mainstream media is in the business of providing fac-
tual information, people may understandably assume that the maps they're looking at are accurate.
But maps that lie flat lie, and there's nothing anybody can do about it — except maybe understand
the nature of the distortions and appreciate that flat maps should be interpreted with a certain amount
of caution.
There's an old saying in cartography: Close counts in horseshoes, nuclear war, and map projections.
(Actually, I just now made that up; but because this chapter is all about lying, what the heck!) Carto-
graphers know projections lie, so their objective is to get as close to reality as possible. But enough of
this blabber about maps that lie, it's time to consider a practical example that involves some honest-
to-goodness maps. Or rather, some not-so-honest-to-goodness maps.
