Global Explorers: Our Changing World · 6th Class · Mapping the World · Spring Term

Map Projections: Representing a Sphere

Understand the challenges of representing a 3D Earth on a 2D map and explore different map projections.

• NCCA Curriculum Specifications
• NCCA: Primary - Maps, Globes and Graph Work
• NCCA: Primary - Using Maps

About This Topic

Ordnance Survey (OS) mastery is a foundational geographic skill that helps 6th Class students to interpret the world around them. Using 1:50,000 scale maps, students learn to translate 2D symbols into 3D landscapes. This topic covers essential skills like using four and six-figure grid references, calculating actual distances using the map scale, and interpreting contour lines to understand elevation and slope. These skills are central to the NCCA Geography curriculum, fostering spatial awareness and graphicacy.

Beyond the classroom, map reading is a vital life skill for navigation and planning. It encourages students to look closer at their local environment and understand how human features like roads and heritage sites interact with natural features like rivers and hills. Students grasp this concept faster through structured games and collaborative 'treasure hunts' using real OS maps.

Key Questions

1. Explain why all flat maps distort the Earth's surface.
2. Compare and contrast the advantages and disadvantages of different map projections.
3. Evaluate the suitability of various map projections for specific geographical tasks.

Learning Objectives

• Explain why all flat maps inherently distort the Earth's surface.
• Compare and contrast the advantages and disadvantages of at least three different map projections (e.g., Mercator, Gall-Peters, Robinson).
• Evaluate the suitability of specific map projections for tasks like navigation, thematic mapping, or global communication.
• Identify the type of distortion (area, shape, distance, direction) present in common map projections.

Before You Start

Introduction to Maps and Globes

Why: Students need a basic understanding of what maps and globes are and their purpose before exploring the complexities of map projections.

Basic Map Features (Scale, Symbols, Grid References)

Why: Understanding how maps represent reality on a smaller scale is foundational to grasping the challenges of flattening a sphere.

Key Vocabulary

Map Projection	A method of representing the three-dimensional surface of the Earth onto a two-dimensional map, which always involves some distortion.
Distortion	The alteration of the shape, size, distance, or direction of features when representing the curved surface of the Earth on a flat map.
Mercator Projection	A cylindrical map projection that preserves shape and direction but distorts area, making landmasses near the poles appear much larger than they are.
Equal-Area Projection	A map projection that maintains the correct relative area of landmasses, though shape and distance may be distorted.
Conformal Projection	A map projection that preserves angles and shapes locally, but distorts area and distance away from standard lines.

Watch Out for These Misconceptions

Common Misconception

Contour lines are actual lines drawn on the ground in real life.

What to Teach Instead

Some students take maps too literally. Use a 3D model or a walk on a local hill to explain that these are imaginary lines connecting points of equal height, helping us 'see' the shape of the land on paper.

Common Misconception

The 'top' of the map is always uphill.

What to Teach Instead

Students often confuse North with 'up.' Peer discussion and checking spot heights on a map can help them realize that a river can flow toward the top of the map if the land is sloping downward in that direction.

Active Learning Ideas

Inquiry Circle: The Great Map Scavenger Hunt

In small groups, students use a local OS map to find specific features using 6-figure grid references. They must identify a church, a bridge, and a specific height above sea level, recording the symbol and name for each.

40 min·Small Groups

Simulation Game: Contour Clay Models

Students look at a simple contour map of a hill and recreate it using layers of playdough or clay. Each layer represents a 10-meter interval, helping them visualize how close lines represent steep slopes and wide lines represent gentle ones.

45 min·Individual

Think-Pair-Share: Route Planning

Pairs are given a starting point and a destination on a map. They must plan the 'easiest' walking route, taking into account distance (using the scale) and elevation (avoiding steep hills), then explain their choice to another pair.

25 min·Pairs

Real-World Connections

• Naval navigators historically relied on the Mercator projection for its accurate representation of direction, allowing them to plot courses using rhumb lines, though it significantly exaggerates landmasses near the poles.
• Cartographers creating world atlases often use projections like the Robinson or Winkel Tripel, which offer a compromise between distorting area, shape, distance, and direction to provide a visually pleasing and generally accurate representation of the entire globe.
• Geographers creating thematic maps showing population density or climate zones might choose an equal-area projection to ensure that the relative sizes of countries or regions accurately reflect the data being presented.

Assessment Ideas

Exit Ticket

Provide students with images of three different map projections (e.g., Mercator, Gall-Peters, a world map from an atlas). Ask them to write one sentence explaining the main advantage of each projection and one sentence explaining its main disadvantage.

Quick Check

Display a world map and ask students to identify which type of distortion (area, shape, distance, or direction) is most evident in the representation of Africa compared to Greenland. Have them justify their answer by referencing the projection's characteristics.

Discussion Prompt

Pose the question: 'If you were designing a map for a global climate change conference, which type of map projection would you choose and why? Consider what information is most critical for delegates to understand.' Facilitate a class discussion where students defend their choices.

Frequently Asked Questions

What does a 1:50,000 scale actually mean?

It means that 1 centimeter on the map represents 50,000 centimeters (or 500 meters) in the real world. For 6th Class students, a simple rule of thumb is that 2cm on the map equals 1 kilometer on the ground. This helps them calculate walking distances for hikes or trips.

Why do we still use paper maps in the age of GPS?

Paper maps don't run out of battery and provide a much wider view of the landscape than a small screen. Learning to read them builds a 'mental map' of an area and helps students understand the relationship between different landmarks, which is essential for safe navigation.

How do you read a six-figure grid reference?

Remember the rule: 'Along the corridor and up the stairs.' The first three digits refer to the Eastings (horizontal), and the last three refer to the Northings (vertical). The third and sixth digits are estimates of how many tenths of the way across the square the point is.

How can active learning help students master map skills?

Map skills can feel abstract until they are applied. Active learning, like building 3D models from contour lines or competing in grid-reference bingo, turns symbols into a game. This hands-on application ensures students are actually interpreting the data rather than just memorizing a legend.