Map Projections
Flattening a globe distorts size, shape or distance.
About this topic
A globe is the only truly accurate model of Earth, because flattening a sphere onto paper inevitably distorts size, shape, distance or direction. Projections are different mathematical ways of doing the flattening, and every one of them is a compromise. Imagine peeling an orange and trying to press the skin flat: it must stretch or tear. Cartographers choose which property to keep and which to sacrifice.
The Mercator projection preserves angles and straight lines of constant compass bearing, so it is useful for navigation, but it exaggerates areas near the poles (Greenland looks as big as Africa, though Africa is 14 times larger). The Peters or Gall-Peters projection shows area accurately but distorts shapes, making continents look stretched. Robinson and Winkel Tripel projections are compromises that keep every distortion moderate, which is why atlases and organisations such as National Geographic have used them for world maps.
Choosing a projection depends on the purpose: a sailor wants Mercator, a student comparing country sizes wants an equal-area map, and a wall poster may use a compromise. A common misconception is that the Mercator map is simply wrong; it is accurate for the job it was designed for. Being aware of distortion helps avoid wrong impressions, such as thinking Russia or Canada is far larger relative to tropical countries than it really is.
Key ideas
- Mercator exaggerates polar areas
- Equal-area maps keep size
- No flat map is perfect
Quick check
Use cases: where Map Projections helps
- Homework: review the key idea behind Map Projections before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Map Projections without notes.
- Visual learning: play with the interactive lab to see how Map Projections changes when you adjust its inputs.
- Teaching a friend: explain Map Projections in your own words, then compare your version with the key ideas.
Geography helps with city planning, climate, trade and migration.
Frequently asked questions
What is Map Projections?
Flattening a globe distorts size, shape or distance.
What will I learn in Map Projections?
Mercator exaggerates polar areas. Equal-area maps keep size. No flat map is perfect.
Is Map Projections part of Geography?
Yes. It is one of 40 Geography topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Map Projections lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Map Projections?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.