USGS Learning Web :: Lesson Plans :: Exploring Maps

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Lesson 3 Guide: Information

Activities

On the Trail of Knowledge -- plotting data on maps to see spatial relationships
Maps With a Spin -- making thematic maps that convey a message

Link to Lesson 3: Information

Notes

This lesson explores thematic maps: maps that show information on single topics. Characteristics of thematic maps are scale, context, and theme. The design of a thematic map considers the purpose of the map. A typical thematic map consists of a base map with selected spatial data plotted on it. A thematic map needs a descriptive title and an explanation. In plotting spatial data and making thematic maps, students will come to appreciate the diversity of information that can be shown on thematic maps.

On the Trail of Knowledge has students plot spatial data on a base map to see the information better. The students evaluate the data, plot points, and consider what the map shows.

Maps With a Spin has students use maps to present alternative proposals for the location of a new airport. Students gather data, make maps, and represent different points of view in a mock town meeting.

Glossary

base map	a map showing certain fundamental information on which can be compiled additional, specialized data.
compilation	production of a new map from existing maps, aerial photographs, and other sources.
context	the interrelated conditions in which something exists.
distortion	the lack of proper proportion; directions, shapes, distances, and sizes of areas may be shown inaccurately.
generalization	the simplification of data by eliminating unneeded detailed data.
grouping	the simplification of data by sorting data into similar sets.
isoline	a line through points of equal value.
map design	the choices made in creating a map; decisions are generally based on the maps purpose, intended audience, and characteristics of the spatial data.
orientation	alignment, usually in reference to points on the compass.
qualitative	related to quality or kind.
quantitative	related to quantity, value, or amount.
scale	the relationship of the size of a feature on a map to its size in reality.
bar scale	scale shown by a line, which is labeled to represent a stated distance.
representative fraction scale	scale indicated by a ratio of one unit on the map to some number of the same units on the ground, for example 1/24,000.
verbal scale	scale indicated by a phrase such as "one inch represents one mile."
large scale	good for showing detail in small areas.
small scale	good for showing a general view of a large area.
spatial data	information pertaining to a place linked to coordinates or other positional information.
thematic map	a map designed to show information on a single topic.

Answers to questions

On the Trail of Knowledge

Instruction 1 The lowest and highest magnitude values are 4.0 and 6.0 respectively. Mid-Atlantic earthquakes would be considered medium-magnitude.

Instruction 2 Symbols for plotting the data should be small, perhaps points. Earthquakes of magnitude 4, 5, and 6 might be shown in different colors.

Instruction 3 A descriptive title might be "Earthquakes of the Mid-Atlantic Ocean Floor, 1990." Thematic maps generally include the authors' names and the dates the map were made. A legend should include an example of each symbol used and an explanation of its meaning.

Instruction 4 The data plotted on this map reveal an S-shaped spatial pattern. Variations in magnitude seem to have a random pattern. The fact that two tsunami warning centers monitor the Pacific Ocean, while none monitors the Atlantic, indicates that magnitudes of earthquakes in the Pacific are expected to be much higher than those recorded in the Atlantic. (See the quotation from Magellan on the reverse of the poster.)

Maps With a Spin

Instruction 1 County and municipal governments may be good sources of data.

Instruction 3 Sort the data into categories defined by the class, such as economic data, transportation data, or land use data.

Instruction 4 In evaluating data, groups should look for data that relate to their interests - data that may support their point of view. Groups may want to keep their ideas and decisions secret from opposing groups.

Instruction 5 Final copies of materials for the town meeting should be neat and lettering should be large enough for presentation. Groups should plan their presentations: who will do what, when, where, and how. Arrangements for any special presentation plans (for example a slide presentation) should be coordinated with the moderator of the town meeting ahead of time.

Instruction 6 Before the town meeting, decide who will act as moderator. As the meeting begins, restate the time limits and the order of presentation. After presentations and rebuttals, vote to decide which plan the town should recommend to the voters. If time is left, evaluate the role of maps in the presentations.