Mapping Projections in Cartography

Mapping Projections

What is a Mapping Projection?

• A mapping projection is a way to represent the curved surface of the Earth on a 2D map
• It's a mathematical method to transform 3D geographic coordinates (latitude and longitude) into 2D Cartesian coordinates (x and y)

Types of Mapping Projections

• Cylindrical Projections
  • Examples: Mercator, Gall-Peters, and Plate Carrée
  • Characteristics:
    • Preserve shape and size well at the equator
    • Distort shape and size near the poles
• Conical Projections
  • Examples: Albers and Lambert Conformal Conic
  • Characteristics:
    • Preserve shape and size well at standard parallels
    • Distort shape and size away from standard parallels
• Azimuthal Projections
  • Examples: Azimuthal Equidistant and Stereographic
  • Characteristics:
    • Preserve distances and directions from the center
    • Distort shape and size away from the center

Important Projection Properties

• Conformality: Preserves angles and shapes well
• Equidistance: Preserves distances from the center
• Equivalence: Preserves area and shape
• Azimuthality: Preserves directions from the center

Common Mapping Projections

• Mercator Projection: Popular for navigation, but distorts shape and size near the poles
• Gall-Peters Projection: Attempts to preserve area and shape, but distorts near the poles
• Winkel Tripel Projection: Compromises between shape, size, and direction, making it a popular choice for general-purpose mapping

Key Takeaways

• Each mapping projection has its strengths and weaknesses
• Choosing the right projection depends on the specific mapping application and the importance of preserving certain properties (shape, size, direction, or area)