LESSON PLAN: Map Projections
LEVEL: Advanced
MAP PROJECTIONS
Related topics: latitude and longitude
OVERVIEW
In this lesson, students will analyze how map projection affects the appearance of Earth’s features. They will
compare different projections and identify which map projection was used for a map.
MATERIALS NEEDED
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World Religions Map (Home >> World >> Maps for the World >> World Religions Map)
World Political Map (Home >> World >> Maps for the World >> World Political Map: Advanced)
ACTIVITIES
Activity 1 helps students understand why all maps are distorted.
Activity 2 provides an opportunity for students to analyze the accuracies and inaccuracies of different map
projections.
OBJECTIVES
Students will describe how map projections affect the appearance of Earth’s features.
Students will identify map projections.
NATIONAL GEOGRAPHY STANDARDS
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How to use maps and other geographic representations, tools, and technologies to acquire, process, and report
information from a spatial perspective
How to analyze the spatial organization of people, places, and environments on Earth’s surface
BACKGROUND INFORMATION
Map projection is the systematic transformation of locations on Earth’s spherical surface to locations on the flat
surface of a map. It is impossible to represent on a flat map the spatial relationships of angle, distance, direction,
and area that only can be shown accurately on a globe. Therefore, all map projections involve some distortion.
The degree of distortion is somewhat less on large-scale maps than on small-scale maps.
The projection system a cartographer chooses depends on the size and location of the area being projected and on
the purpose of the map. The characteristics of the projections that will be discussed in this lesson are presented in
the chart below.
Projection
Mercator
Goode’s Interrupted Homolosine
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Characteristics
 shows the shape of land masses
correctly but distorts their areas
 the farther away from the Equator, the
greater the distortion
 shows land masses with a minimum of
shape distortion by positioning each
section on a separate central meridian
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LESSON PLAN: Map Projections
LEVEL: Advanced

Robinson
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
shapes and sizes of land masses are
represented accurately
shows an uninterrupted view
maintains overall shape and area
relationships without extreme distortion
ACTIVITY 1
Write the following statement on the board: All maps show a distorted view of Earth’s surface.
Ask students to explain why the statement is true. [It is not possible to accurately represent the curved surface of
Earth on the flat surface of a map.] If students have difficulty with this concept, you might have them do Activity
1 from Map Projections (Intermediate level).
Explain that cartographers use different map projections to minimize the distortion of different areas on a map.
Have students work individually or as a group to complete the worksheet titled “Analyzing Map Projections.”
ACTIVITY 2
Have students examine a globe to determine the characteristics of lines of latitude and lines of longitude. Have
them list the characteristics in a chart.
Suggested responses:
Meridians of Longitude
All meridians of longitude are equal in length
and meet at the Poles.
Meridians of longitude are equally spaced on
each parallel, but the distance between them
decreases toward the Poles.
Meridians cross parallels at right angles.
Parallels of Latitude
The circumference, or length, of parallels of
latitude decreases from the Equator to the
Poles. For example, the circumference of the
parallel at 60º latitude is one-half the
circumference of the Equator.
All lines of latitude are parallel and equally
spaced.
Parallels cross meridians at right angles.
Ask students to explain how the analysis of latitude and longitude helps explain the distortion shown on map
projections. [Distortion is usually greater toward the poles because of the difficulty of showing the curved lines of
longitude. A Mercator Projection shows lines of longitude parallel to one another.]
CONCLUDING AND ASSESSMENT
Display the World Religions Map and the World Political Map. Have students identify which map projection was
used. [World Religions Map: Goode's Interrupted Homolosine Projection; World Political Map: Robinson
Projection] Ask them to explain how they determined their answer.
INTERNET CONNECTIONS
Students can find directions for making a Mercator Projection at
http://interactive2.usgs.gov/learningweb/teachers/exploremaps_lesson2_1.htm
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LESSON PLAN: Map Projections
LEVEL: Advanced
CROSS-CURRICULAR CONNECTIONS
Language Arts
Ask students to imagine the following scenario:
You are responsible for purchasing new maps for your school. What type of map projection would your maps
have? Write the explanation you would use to convince the school board to provide the money for these maps.
ANSWERS TO STUDENT WORKSHEET
A. A Mercator Projection shows the shape of land masses accurately but distorts their sizes.
B. A Goode’s Interrupted Homolosine Projection shows accurate sizes and shapes of land, but is
interrupted in the ocean areas.
C. A Robinson Projection shows accurate sizes, shapes, and relative positions of land with some
distortion near the Poles.
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Name: _______________________________________________________
Date: ___________________
ANALYZING MAP PROJECTIONS
Identify the advantages and disadvantages of each projection below.
A. Mercator Projection
___________________________________________________________________
___________________________________________________________________
B. Goode’s Interrupted Homolosine Projection
________________________________________________________________________
________________________________________________________________________
C. Robinson Projection
_____________________________________________________________________
________________________________________________________________________
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