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I. How To Use and Think About Maps and Spatial Data Sets
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Web Sites
Narration
Maps are geographers' most important tools. In fact, it is said that if something can't be mapped, it is not geography. Maps make up the basic mental images held by geographers who strive to make them more and more accurate. Maps have driven the science for thousands of years.
The use of cartography distinguishes geography from other disciplines. Geographers are constantly relying on maps to communicate their concepts and search for solutions to problems. A map is a two-dimensional or flat scale-model of the earth's surface. Because the earth is spherical in shape, it is impossible to draw a map that is totally accurate on a flat piece of paper. Therefore, all maps "lie" or distort some features of the earth's surface. In order to show the 3D surface of the earth on a flat map, geographers make use of projections. To understand projections, one can imagine a globe with a light inside of it. By wrapping a piece of paper around the lighted globe (perhaps in a cylinder or cone), a cartographer could trace landforms from the globe as they are "projected" onto the paper.
Cartographers make two very important decisions when they create maps. The first is determining which projection they will use; the second is deciding what the scale or level generalization is. It is easy to understand why scale or level of generalization is a key decision. The size of the area under consideration and the level of detail under analysis determine the appropriate scale. Projection decisions are more difficult because the influences of the projection are subtle. There are four types of distortions that result from the surface of the earth being put down as a flat map. The first is shape -- that is, an area can be elongated or squashed. The second is distance -- distance between two points can be increased or decreased. Third, the relative size of the area can be altered. Fourth, the direction from one place to another can be distorted. It is impossible to have a map that shows shape, distance, size, and direction all correctly, although it is possible to have a map that shows one thing correctly. Cartographers have to make decisions about which type of map is most appropriate for each of their projects or questions.
With the advent of computer programs designed to manipulate data, cartography has undergone dramatic change. Geographers now talk about Geographic Information Systems (GIS), which are computer programs designed to manipulate cartographic data and technology related to remote sensing (data collected from satellites and broadcast to the surface of the earth). A GIS is a high-performance computer and software package that processes geographic data and prints it out in cartographic form. The key thing about a GIS is that it stores information about location in layers. Any number of layers of data can be stored in GIS and the computer software can superimpose layers upon other layers. A related technology is Global Positioning Systems (GPS). This is a new technology that enables precise navigation and enables the user to locate any particular point on the surface of the earth and give it accurate latitude and longitude coordinates. Thus, information can be "geocoded," entered into the GIS, and elaborate maps can be made.
Web Sites
To view the following Web sites, please go to "See also" below.
The Teachers' Corner contains links to suggested Web sites. The College Board neither endorses, controls the content of, nor reviews the external Web sites included here. Please note that following links to external Web sites will open a new browser window. If you discover a link that does not work, please let us know by sending an e-mail to apctechsupport@collegeboard.org.
Cartographic Communication
This University of Colorado at Boulder site is a good resource for the use of maps and cartography, particularly the value of maps. Originally developed at the University of Texas. The authors are Kennth E. Foote and Shannon Crum, The Geographer's Craft Project, Department of Gepgraphy, The University of Colorado at Boulder.
Cartography Section of the United Nations
This is an excellent source of digitized maps in pdf format from all over the world. More than 100 general maps and a number of specialized maps. (Acrobat Reader required; there is a link to download the program if you don't have it on your computer.)
Choropleth Map Making
This page introduces choropleth maps, which are one of the most commonly used means of displaying aerial data.
Climographs of Cities
This site contains an interactive map of U.S. cities. Select a city to see its climograph.
Coordinate Systems Overview
A basic introduction to every type of coordinate system in existence. The author is Peter H. Dana, The Geographer's Craft Project, Department of Gepgraphy, The University of Colorado at Boulder.
Map Tools, Free (PDF)
A page with links to a variety of map tools. These will be useful for students who are creating maps for display on a screen. They download immediately to your drive for your use. The tools are: Universal Transverse Mercator Coordinate Tools (pocket size grid), Estimating the Size of an Area, Scales & Rules, Latitude & Longitude Tools, Compass Rose. Several scales and varieties exist for each tool.
Maps: Color Landform Maps of the United States
Several types of digitized maps are available for each of the 50 states. Maps are free.
Maps: Free Outline Maps
Free maps to download and print or use in a computer lesson. From the Houghton/Mifflin home page.
Map Library from Perry Castenada at the University of Texas
Excellent source of digitized maps of all types. One of the best sources for cartographic information on the Internet.
Maps: Resources from the University of Iowa
Extensive list of maps and resources for environmental research. There are separate links to geodata information maps as well as satellite imagery maps.
Map Resources from George Mason University
An excellent resource from GMU, this site includes a Bosnian virtual field trip and cartography resources, including a long list of map servers and GIS servers. However, many from the list are commercial enterprises.
Maps: CSU's Electronic Map Library
List of downloadable maps from California State University, Northridge. Limited in scope, but some are hard to find elsewhere, such as maps by race and religion or ancestry.
National Council for Geographic Education (NCGE)
This is the site map for the NCGE page. Follow your interest by selecting topics.
National Geographic Society
This site has high-quality geography information. Check out the frame on the left and follow other links. The site changes frequently, so check it often.
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