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Mercator vs Equal Earth: Map Projections Explained

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Why A Flat Map Cannot Accurately Represent The Earth

Source: Indian Express
GS I: Geography- Salient features of world’s physical geography

Overview

  • The UN’s support for the Equal Earth projection has revived the debate over the limitations of the traditional Mercator map.
  • No flat map can perfectly represent the three-dimensional Earth, as every projection involves some distortion of area, shape, distance, direction or angles.
  • The Mercator projection is useful for navigation because it preserves local shapes and directions, but it greatly exaggerates the size of regions near the poles.
  • The Equal Earth, Robinson and Winkel Tripel projections offer different approaches to reducing or balancing distortions, depending on the purpose of the map.

Why in the News?

The United Nations has adopted a resolution supporting the use of the Equal Earth map, drawing attention to the limitations of the centuries-old Mercator projection.

News in Brief
  • At a recent UN General Assembly session, 164 countries, including India, supported the Equal Earth map, while the United States voted against the proposal.
  • The resolution is not legally binding, but it reflects growing support for map projections that show the relative size of countries and continents more accurately.
  • The move has renewed the debate on the limitations of map projections and the need for maps suited to different purposes.
Why Does A Flat Map Distort The Earth?
  • The problem is the Earth is not flat.
  • It is a three-dimensional, nearly spherical body, while a conventional map is a two-dimensional surface.
  • Converting the Earth’s curved surface into a flat plane necessarily causes some form of distortion.
  • Depending on the type of projection used, a map may distort:
    • Area
    • Shape
    • Distance
    • Direction
    • Angles
  • Therefore, no single map projection can preserve all geographical properties simultaneously.
Mercator Projection
  • The Mercator projection was introduced by Gerardus Mercator in 1569, mainly to help sailors navigate across the oceans.
  • Its strength lies in preserving local shapes and angles.
  • More importantly, a straight line on the map can represent a constant compass direction, which made it extremely useful for maritime navigation.
  • However, this advantage comes at a cost.
  • To preserve shape and direction, the map stretches regions increasingly as they move away from the equator.
  • As a result, areas near the poles appear much larger than they really are.
  • For instance:
    • Greenland appears disproportionately large.
    • Antarctica appears enormously stretched.
    • Africa and other regions closer to the equator appear relatively smaller.
  • Therefore, the Mercator projection is useful for navigation, but it is not suitable for comparing the actual size of countries and continents.
Equal Earth Projection
  • The Equal Earth projection, developed in 2018, was designed to address one of the major shortcomings of conventional world maps – the inaccurate representation of relative area.
  • It is an equal-area projection, meaning that it preserves the relative size of countries and continents more accurately.
  • This makes it particularly useful for representing:
    • Land area
    • Population distribution
    • Resource distribution
    • Land cover
    • Other thematic and statistical information
  • However, preserving area does not mean eliminating all distortions.
  • The Equal Earth map still compromises on shape, distance, direction and angles.
  • Thus, it offers a better picture of the relative size of landmasses, but it cannot be considered a universally perfect replacement for every other map.
Robinson And Winkel Tripel Projections
  • Some map projections do not attempt to preserve one particular feature perfectly.
  • Instead, they try to keep overall distortion within reasonable limits.

Robinson Projection

  • The Robinson projection provides a visually balanced view of the world by reducing extreme distortions.
  • It does not perfectly preserve area, shape or distance, but offers a more natural-looking representation of the entire Earth.

Winkel Tripel Projection

  • The Winkel Tripel projection also aims to minimise overall distortions related to area, distance and direction.
  • It is widely regarded as useful for general-purpose world maps.
  • Both projections are particularly suitable when the objective is to provide a balanced overall view of the world rather than prioritizing a single geographical property.
Significance of the UN’s Move
  • The debate over map projections is not merely a technical issue.
  • Maps shape how people perceive the world.
  • When some countries or continents appear much larger than they actually are, it can influence our understanding of their geographical size and relative position.
  • The growing preference for equal-area projections can,
    • Improve geographical awareness.
    • Provide a more accurate comparison of the size of landmasses.
    • Reduce misconceptions caused by the enlargement of polar regions.
    • Improve the representation of statistical and thematic data.
  • At the same time, replacing the Mercator map completely would not make sense.
  • It continues to serve an important purpose in navigation.

Different Maps For Different Purposes

Projection Main Advantage Suitable Use
Mercator Preserves angles and direction Navigation
Equal Earth Preserves relative area Thematic and statistical maps
Robinson Provides a balanced overall view General world maps
Winkel Tripel Minimises overall distortion General reference maps
Azimuthal Useful for direction and distance from a central point Polar regions
UPSC Prelims Practice Question

With reference to map projections, consider the following statements:

  1. The Mercator projection is a conformal projection that preserves local angles and shapes.
  2. Equal-area projections preserve the relative area of geographical regions but may distort their shapes.
  3. No flat map projection can simultaneously preserve area, shape, distance and direction everywhere on Earth.

Which of the statements given above are correct?

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Answer: (d)

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