Global Positioning System Reference
In-Depth Information
fied to reduce the more obvious scale inflation at the poles. The Robinson
projection produces a better balance of size and shape at high latitudes and
has been used by the National Geographic Society for some of its world
maps. Polyconic projections, dating to 1820, use di√erent cones at di√erent
latitudes to reduce distortion; these projections were once used exten-
sively to map the contiguous United States.
Interrupted projections change the reference point or line in mid-ocean
in order to minimize distortions on the continents. These maps look like
an orange peel; they are shaped a little like Dymaxion maps but with north
at the top of the map. A common example is the sinusoidal equal-area
projection. Also known as Sanson-Flamsteed , this projection dates back to
1570, contemporary with Mercator. We have seen that equal-area maps are
good for illustrating distribution patterns, and the sinusoidal version is
widely applied for that purpose. Indeed, as Mercator projections were the
natural choice for navigators in the Age of Exploration (and gnomonic
maps are perhaps the natural choice in the airplane age), many cartogra-
phers today think that equal-area maps are the best choice for general use
in the modern world.
FIGURE 4.13. A modern low-distortion map of the world resulting from a Winkel Tripel
projection. NASA image.
 
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