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the Prime Meridian

ectangle) around a globe creates a cylindrical-class map. Cylindrical-class maps are usually centered on the equator. A

planar-class map results from placing a flat surface next to the surface of a globe, so that the two only touch at a single

point, and is most often used to project the poles.

In order to reduce some of the distortion created by projecting a map, cartographers center their maps on a standard

line or point. The points where the developable surface (flat piece of paper with no tears) touches the globe creates the

standard line or point where distortion is minimal. Distortion increases as you move away from the standard line or

point. Generally, cylindrical projections employ the equator as the standard line and thus are greatly distorted in the

higher latitudes. Conical projections typically have a standard line somewhere in the midlatitudes, so this type of

projection is often used for the United States. Planar projections typically have a single standard point because the

developable surface of the plane contacts the globe in only one place.

15. List two advantages that a globe has compared to a map.

16. List two advantages that a map has compared to a globe.

Figure 6 Mercator, Peters, and Goode’s projections


17. The Mercator projection (conformal cylindrical equatorial) maintains the correct shape of landmasses, but not

their sizes. As a result, Greenland (0.8 million square miles) appears larger than the entire continent of Africa

(11.6 million square miles). The Peters projection (equal area cylindrical equatorial) maintains the correct size of

countries, but not their shapes. Goode’s projection maintains the size and shape of landmasses, but interrupts

the oceans. Are you more accustomed to viewing one of these in particular? How do these maps influence your

perception of the world?