Lecture on Map Projections

Introduction to Map Projections

• Definition: Maps attempt to represent countries and continents on a flat surface using map projections.
• Challenge: Impossible to accurately flatten a globe's surface due to latitude and longitude transformation.
• Analogy: Similar to trying to flatten an orange peel.
• Result: All map projections distort the globe’s surface to some extent.

Types and Purposes of Map Projections

• Variability: Over 250 known map projections; virtually infinite due to varying purposes and acceptable distortions.
• General Categories: Map projections can be divided into seven groups, focusing on different aspects depending on the map's purpose.

Mercator Projection

• Origin: Created by Gerardus Mercator in 1569, during European colonialism.
• Function: Represents constant courses as straight lines for navigation.
• Distortion: Inflates sizes of objects away from the equator; accurate near the equator but distorts poles.
• Examples of Distortion:
  • Greenland vs. Africa
  • Madagascar vs. UK
  • Alaska vs. Brazil
  • Antarctica's exaggerated size

Shift to More Accurate Projections

• Robinson Projection
  • Developed in 1987, adopted by National Geographic in 1988.
  • Minimizes size distortion, only at poles.
• Vandergrinton Projection: Reduced Mercator's distortion at the equator, concentrated on poles.

Other Map Projections

• Transverse Mercator: Different angle of the Mercator, with unique distortions.
• Lambert Conformal Conic Projection
  • Origin: 1772, no Antarctica depicted.
  • Uses in aviation for representing flight routes as straight lines.
• Stereographic Projection: Centered on the north pole, used in ancient maps.
• Modern Accurate Projections
  • Airy Minimum Error Projection: Globe cut in half, minimal error depiction.
  • Van Leeuwen’s GC and Adam’s Hemispheres: Use dual shapes for depiction.

Innovative and Unique Projections

• Cahill Conformal Butterfly: World in 8 triangles, accurate continent sizes.
• Cahill Keyes Projection: Similar to Butterfly, with additional piece for Antarctica.
• Chaiselange Conformal: Unique shape, difficult distance perception.
• Demaxion-like Conformal: 20-sided shape for accurate depiction.
• Schierning 1: Extreme stretching of Antarctica.

Conclusion

• Purpose: Map projections exist to represent the globe on a flat surface.
• Inaccuracy: All projections are necessarily distorted.
• Diversity: Hundreds of projections exist, each with unique characteristics.
• Further Exploration: Encouraged to explore more about map projections through online resources.

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This concludes the overview on map projections, their purposes, and their various forms and distortions.