Lecture on Map Projections

Introduction

• A globe cannot be turned into a flat map without distortion.
• The dilemma: surface of a sphere cannot be represented as a plane without distortion.

Historical Context

• Since the 1500s, mathematicians developed algorithms to translate the globe into flat maps using projection.

Projection Methods

Cylindrical Projection

• Popular for rectangular maps.
• Imagine a cylinder over the globe, projecting each point onto the cylinder's surface.
• When unrolled, it creates a flat, rectangular map.

Impact of Projection

• Every projection has trade-offs:
  • Shape
  • Distance
  • Direction
  • Land area.

Mercator Projection

• Widely studied in schools, used by Google Maps.
• Preserves country shapes, especially useful for navigation.
• Designed so a line drawn between two points provides an exact compass angle.
• Issues with size representation: Africa vs. Greenland.
  • On the Mercator map, Greenland appears as large as Africa, but is actually 14 times smaller.
• Criticized for perpetuating imperialist attitudes by distorting size.

Gall-Peters Projection

• An equal-area map where size comparison is accurate.
• Distorts the shape of countries, stretches them.

Impact of GPS

• 1960s: Satellite GPS eliminated the need for paper maps in navigation.
• Map projections shifted toward aesthetics, design, and presentation.
• Mercator map, vital pre-GPS, is considered misleading by modern cartographers.

Modern Cartography

• Web mapping tools like Google Maps still use Mercator for practical reasons (city navigation).
• World maps rarely use Mercator.
• Use various projections that balance size and shape distortion.

Winkel Tripel Projection

• Adopted by National Geographic Society in 1998.
• Offers a balance between size and shape accuracy.

Conclusion

• No single "right" projection exists.
• A globe is the best representation of Earth.
• Flat maps involve trade-offs in projections.
• A vast library of projections provides different perspectives on Earth.