by
(For a greatly expanded/updated version of article, see "Mapping Reality: Life, Communication, and Everything,"
Parts 1 and 2, in the January 2006 and April 2006 issues of The Watermark.)
Quick!
What's the answer to this simple question from third-grade geography class:
"Which country is larger, Greenland or Australia?" If third grade is a dim
memory, you may want to consult the map [Figure 1] that is similar to the one I had in
third grade.
This map is called a Mercator projection after the 16th-century cartographer Gerardus Mercator. Mercator was an early technical communicator. He took latitude, longitude, coastal and country boundaries, and put this information into a succinct, concise textual and graphical communication (a map). His work was so influential that he defined how people viewed our planet for four centuries.
On his map, Greenland appears considerably larger than Australia. This observation troubled me in third grade when my class studied the seven continents. Australia was listed as a continent along with Africa, Asia, and others, but Greenland was classified only as an island. To my third-grade mind that seemed unfair since Greenland was obviously larger than Australia. I asked my teacher about this cartographic conundrum, but she didn't know the answer.
I finally
learned the explanation years later when I discovered I had been deceived. Mercator's
map distorts the truth. Greenland (with a surface area of 840,000 square miles) is really
less than one-third the size of Australia (with 2,968,000 square miles).
Appearances deceive because, on this map, meridians (the vertical lines) run parallel. In reality, meridians are farthest apart at the equator and squeeze together to single points at both poles. Thus, the closer a country is to either of the polar regions, the greater its inflated size on this map.
On an alternate map, such as a Goode-Homolosine projection [Figure 2], Greenland correctly appears significantly smaller than Australia.
Although this map more accurately shows the relative sizes of countries, the distances between countries are somewhat harder to grasp. Furthermore, this map resembles a flattened orange peel more than a clear image of our planet. Thus, this map also has distortions.
Which is a better map? Distortions plague all maps because maps are flat, but the earth
is round. Whenever three dimensions get squashed down to two, distortions are inevitable.
You might think the solution to the distortion dilemma is to keep the map three dimensional—as in a globe. Globes, however, depict the earth on a very small scale and have limited uses. Globes excel in communicating the Big Picture but inadequately divulge accurate details. Imagine a globe large enough to function as a road map of the United States [Figure 3]. Now imagine trying to fit that globe into the glove compartment of your car.
Mapmaking is a form of technical communication, and in a broader sense, technical communication maps information. These information maps may be text, a graphic, or combination of both. A schematic maps an object, a flowchart maps a process, a tree maps hierarchical relationships. The text in an operator's manual maps the way your widget can and cannot be used.
The mapping of information is a great responsibility because it must be concise, understandable, and accurate. It defines how we view the objects, processes, and organizations around us. Mapping information in a compelling manner that does not distort reality is a tough job.
Technical Cartographers, we are modern media Mercators, and may all our information maps be good ones.
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