True Sizes

EarthView co-coordinator Dr. Hayes-Bohanan (first name James) saw this Bitstrip cartoon recently, and added the caption about Greenland. He is not really mad at Greenland of course; it is a geographer's joke about map projections.

Many people who enter EarthView are surprised to see that Greenland is not nearly as large as they had thought, and at first many think it must be a mistake. Globes, however, are the only kinds of maps that maintain the size, shape, direction, AND distance correctly. Flattening all or part of a map requires a projection, and one or more of these spatial properties is always sacrificed to emphasize the others.

Unfortunately, the very most common projection is the Mercator, which maintains direction correctly, but distorts size, shape, and distance, especially at high latitudes (near the north and south poles). The projection is ideal for navigation, but it is not good for understanding geographic patterns, especially at a global scale. Still, it appears most commonly in schools, textbooks, and on television news.

Fortunately, The True Size is a fun way to overcome this problem. This composite shows Greenland as it appears on Mercator maps and Greenland as it would appear if moved to Argentina.

This map is also an excellent way for learners of any age to develop spatial thinking. If we are studying a country that is not familiar, we can "pull" it to a more familiar area to get a better sense of its size and shape. The country of Syria, for example, is about the size and shape of New England, excluding northern Maine.

Another way, of course, is to learn more about projections and to select a projection that is appropriate for a particular use. The Map Projections page at Geography@About.com is a great place to start.