THE ROUND EARTH ON FLAT PAPER
Geographers use a variety of tools to carry out their work. The tools that most people identify with geography are those that are still most important to geographers today — globes and maps. Modern geographers, however, also use tools such as aerial photographs, satellite images, and computer programs to help them analyze the interactions between people and their environments. The best tool to use often depends on the geographic theme that is the focus of the research. Globes and maps are useful models of the earth. However, globes and maps do not provide perfect representations of the earth. Each has specific advantages as well as disadvantages.
Globes. The most important advantages of globes relate to their shape. A globe is the only model of the earth in the shape of a sphere, just like the earth. A globe, then, provides the most accurate representation of the shape of the earth. Because it is true to scale, the landmasses and bodies of water the globe illustrates have the same shapes as they do on the earth’s surface. When you look at Greenland on a globe, for example, its true shape is what you see. You can also compare its size to any other land body. In addition, a globe accurately represents the earth’s grid of parallels and meridians, as well as direction and distance from one place to another.
Among the disadvantages of globes is that they often are not practical to use. Globes are expensive and most are too big and bulky to carry around. In addition, people can view only one-half of a globe at a time. This makes it impossible, for example, to look at Canada and India at the same time because they lie on opposite sides of the globe, just as they lie on opposite sides of the earth. Another disadvantage of globes concerns the problem of detail. Because globes represent the entire earth, the individual areas that they illustrate are relatively small. As a result, globes cannot show the detailed features of an area, such as roads, streams, forests, and parks.
The oldest preserved globe is kept and displayed to the public in a museum in Germany. This wooden globe was made in 1492. It is 15 cm in diameter. The globemaker drew on it the land and water bodies that he thought existed. What is interesting about this globe is that it shows the world as Columbus thought of it.
Maps. Maps are flat representations of the earth. Maps vary in size from small maps that appear in pocket size to huge wall maps. Maps also vary in purpose.
One of the most obvious advantages of maps over globes is that they are more convenient to use. Maps can be rolled and folded and are easy to carry around. Maps and related material can also be collected in an atlas to provide an easy-to-use reference. Another advantage of maps is that they can show the earth’s entire surface at one time, or can show specific details. Maps can also present information about a wide range of topics related to both physical and cultural features of the earth. Using different colors and symbols, maps can illustrate many kinds of topics, including rainfall, mineral resources, and religions. Presenting such a variety of information about an area often helps geographers to see regions and relationships otherwise difficult to visualize.
On the other hand it is impossible to accurately show a three- dimensional object like the earth on a flat, two-dimensional map. For this reason all maps have one or more inaccuracies, called distortions. The problem of distortion remains the major disadvantage of maps.
1. What tools do geographers use?
2. What are the major advantages and disadvantages of a) globes and b) maps?
3. Why is cartography related to all the fields of geography?
4. Why do maps have distortions?