LEARN NC was a program of the University of North Carolina at Chapel Hill School of Education from 1997 – 2013. It provided lesson plans, professional development, and innovative web resources to support teachers, build community, and improve K-12 education in North Carolina. Learn NC is no longer supported by the School of Education – this is a historical archive of their website.

Let’s start with the basics. What is a map?

Ask that question in a classroom — or any other setting — and you’ll get a variety of responses, most having to do with geography or finding your way from place to place. The dictionary on my Macintosh offers this as the first definition under map, n.:

a diagrammatic representation of an area of land or sea showing physical features, cities, roads, etc.

This, in other words, is a map:

Figure 3-1. Physical map of the world, using Robinson projection.

physical map of the world

But what about the “et cetera” in that definition? That’s a pretty big “et cetera.” Lots of things are represented on maps besides physical reality — climate, for example, or population density, or economic production.

Figure 3-2. United States population density, 2000.

U.S. map showing population density

Figure 3-3. Map of Australia showing climatic regions.

climate map of Australia

Beyond geography

In fact, a “map” doesn’t even have to have anything to do with geography. A scientist might map electron densities

Figure 3-4. An electron density map is a diagram of a molecular structure showing the probability that an electron will be present at any given location.

electron density map

…or the genome of a plant pathogen.

Figure 3-5. Map of a genomic segment from Spiroplasma kunkelii.

genetic map

A broad definition

More broadly, we could define a map simply as a visual representation of data. That data might describe physical location (via latitude and longitude, for example) — or it might not. And the visual representation might be a two-dimensional diagram — but then again, it might not. Actually, the representation might not even be visual.

The map skills I want to talk about have mainly to do with geography, but before we get there, I want take a closer look at what it means to “visually represent data.” Understanding that will help us understand what skills are necessary to create and read maps — and, in turn, what skills can be developed through mapping practice. This is going to take a little math, so hang on. If you’re short on time, you can skip ahead, but if you stick with me, I’ll try to make it worth your while.