Maps: A Unit Study

Gerardus Mercator was born on March 5, 1512, in Flanders to a poor shoemaker. Thanks to the patronage of a wealthy uncle, he was able to pursue his interest in mathematics and astronomy. Mercator developed an interesting set of skills including engraving and calligraphy. He was also a scientific instrument maker, curriculum developer, surveyor, had an interest in geography, a degree in philosophy, and had been trained for the priesthood. Many of these skills came together when he saw the plight of European navigators traveling long distances while trying to use the maps that were available at the time.

The Problem Mercator Solved

What were needed were straight lines. The problem was how to represent a round world on a flat surface. Globes could be used, but most navigators wanted a flat surface that they could easily carry with them and lay out flat on a table to study. Mercator painstakingly researched the maps and other geographical information that was available at the time. He came up with a way to project meridians and parallels onto cylinders so that the intersection of these lines formed 90 degree angles. In other words, the meridians and parallels were straight lines. The resulting maps provided consistent compass bearings, providing an accurate ratio of latitude to longitude.

The History of Cartography

Cartography is the science of mapmaking. The earliest maps originated in ancient Babylonia, but mapmaking really got its start in ancient Greece around the time of Aristotle. The first “world map” was developed by Ptolemy in his book Geogrophia. Though not a pictorial representation, later cartographers used the coordinates he supplied to create what is known as the Ptolemy world map. These maps were drawn and illuminated by hand, which made them very rare.

It wasn’t until the age of exploration that maps useful for navigation were created, charting latitudes, coastlines, and other features necessary to navigation.

Mercator’s 1569 cylindrical map projection revolutionized cartography. And it was Mercator who coined the term Atlas.

Why Your Map is Deceiving

The Mercator projection, and other projections that followed, became an easy way to print maps in books, atlases, and other material. Any line on a Mercator map is a true straight line and always the shortest distance between two points. But there is one important thing to remember about these projections — every map has distortions either in shape, distance, direction, or land mass area. Because of these distortions, they do not accurately represent the sizes of countries relative to one another. Depending on the projection, the farther away from the center of the map you get, the more distorted the size of the land masses becomes — great for navigating, but not so great for visualizing the earth.

Further Investigation

Gerardus Mercator
Just the facts from the Galileo Project.

Mercator Projection
Just the facts from Penn State.

Mercator’s Projection
An explanation of how it works.

Old Maps — Brief History of Cartography
Easy-to-read summary with map examples.

Topographical Map Symbols
Also for older students.

Activities

Mercator World Map
View the entire map and zoom in for more detail (very large file — make take some time to load).

Map Reading Activity
From Enchanted Learning.

Making Sense of Maps
Great interactive site hosted by the American Social History Project where students learn about the history of maps, the vocabulary of maps, and the use of maps, and then answer questions that demonstrate their understanding of the material.

Types of Maps
Interactive from MSNucleus.org.

Interactive Map Maker {Free}
Great tool that a student can use to create his own maps.

Map Skills
Interactive quiz that can be used for wrapping up.

Books

Maps and Globes by Jack Knowlton
Reading Rainbow selection that helps young people understand the basics of reading and using maps and globes.

The History of Cartography edited by J.B. Harley and David Woodward
Free download (chapter by chapter) subtitled Cartography in Prehistoric, Ancient, and Medieval Europe and the Mediterranean published by University of Chicago Press. Probably too much for most, but interesting!

Unit Studies & Lesson Plans

Map Adventures
Excellent set of seven lessons from the USGS aimed at younger students.

Introduction to the World Map
Lesson plan that emphasizes the differences between a globe and a map.

Latitude on World Maps
Lesson plan that has students finding the latitude of certain locations.

Longitude on World Maps
Lesson plan that has students finding the longitude of certain locations.

The Global Grid System
Lesson plan that follows the previous two by finding locations using latitudinal and longitudinal coordinates.

World Projections
Lesson plan that discusses the problems with and differences between map projections.

Maps and Mapping
Lots of activities in this lesson plan from Harvard covering reading, making, and understanding maps.

Using Maps and Globes
Quality lesson plan from Core Knowledge that culminates in a geography notebook. Excellent printables!

Cardinal Directions Resources & Mapmaker Kit {Free}
Helps for learning the four main directions — foundational to finding things on a map!

Wrong-Way Corrigan: A Compass Unit Study
One of our other units covering compasses, the compass rose, and directions.

Teacher’s Guide: Analyzing Maps
Download from the Library of Congress with guidelines and ideas for helping students analyze historical maps as primary source documents.