[Athena] [Curriculum] [Earth Resources]
Cartography -
the Art of Making Maps, the Science of Where You Are

In this series, you will use maps of many scales as you zoom down from space to Bellevue, Washington (USA), where you can continue on and tour an urban wetlands nature trail. We begin with:

World Maps

Hundreds of years ago, our ancestors had only a vague idea of how large our world is. Many brave sailors and travelers set out to explore the world, and some were never able to return to their homes.
Christopher Columbus and Ferdinand Magellan both sailed west from Europe hoping to reach the fabulous spice-producing region of Southeast Asia. For each, the world was a larger place than they imagined: Columbus found a continent and Magellan crossed our world's widest ocean.

These seafarers had the best maps of their time, but the maps could not show what was not known. Their voyages would have been very different if only they had known what we know today.

The Earth photographed by an astronaut on Apollo 11.

What is a Map?

A map is a way to show information. The cartographer makes the map to show the information he or she wants to present. A map might:
You can choose the right map to tell you exactly what you want to know.


The Earth is a sphere, so we cannot make a map that shows all of it at once without distortions. Cartographers have designed many different ways of mapping the Earth (these are called projections). Most maps have north at the top, south at the bottom, east to the right, and west to the left, but not always.
Here are two different projections of the whole Earth that show outlines of the continents.
In this elliptical projection, the Earth's surface is stretched so that the continents have about the right shape and size (although Antarctica is too big).
In this familiar rectangular projection longitude and latitude are used as x and y values for a graph. This kind of map is easy to draw, but the continents are distorted. The distortion is less near the equator and becomes greater to the north and south. After all, in this projection, the north and south poles are not points, but the lines at the top and bottom of the map!

Activity 1: Where was Apollo 11?

  1. Use this Activity 1 page or scroll up to the top of the page and look at the shapes of the land you can see beneath the clouds.
  2. Scroll down to the maps in the Projections section and find the same shapes on one of the maps. (Hint: is north at the top of the photograph?)
  3. Apollo 11 had to be directly above some place on Earth. Find that point. (Hint: where is the center of the photograph?)

Activity 2: Is This Image a Map?

This image of the Western Hemisphere was taken with an infrared camera on the NOAA weather satellite GOES-6. Our hands feel infrared radiation as heat, but our eyes can't see it at all. Everything gives off infrared; the amount given off depends on the object's temperature. More infrared means a higher temperature.
The scientists who processed the data from this camera first took all the data points warmer than a certain temperature and assumed those points were ocean or land. Using a map, they colored these data points blue if they were ocean and green or brown if they were land.

They assumed that all the rest of the points were clouds. In the Earth's atmosphere, the higher you go the colder it is. Clouds high in the atmosphere are cold and clouds low to the ground are warmer. The scientists colored the warm cloud points gray and the colder cloud points white.

  1. Unlike the view of the Earth at the top of this page, this image is not a photograph. Compare the two images and explain one way to tell a photograph from a data image.
  2. Do you think this image is a map? Why or why not?
View a larger image (402kb) or read the image caption.

Zoom down to Maps of North America and the USA.

Image Credits

The Earth - Bill Arnett presents a NASA photo from Apollo-11.

Western Hemisphere from Space - Los Alamos National Laboratory presents an image derived from an infrared camera on the NOAA GOES-6 satellite.

Line Maps - Xerox PARC Map Viewer allows you to view maps of any portion of the Earth.

Related Information

Written by: Rob Westcott, Hugh Anderson, and Lorraine Johnson.

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Last Modified Fri Jan 24 23:20:54 1997