Why Flat Maps Cannot Accurately Represent the Earth
Why in News
The growing discussion around the Equal Earth projection as an alternative to the widely used Mercator projection has renewed attention to how different map projections represent the size, shape and distance of geographical regions.
Key Highlights
- Earth is a three dimensional, approximately spherical body, whereas maps depict it on a two dimensional surface. As a result, every map projection involves some degree of distortion.
- The Mercator projection preserves angles and directions, making it valuable for navigation, but significantly enlarges the apparent size of regions at higher latitudes.
- This distortion can make Greenland appear comparable in size to Africa, even though Africa is vastly larger.
- The Equal Earth projection is designed to preserve relative areas, offering a more proportionate representation of global land masses, including regions of the Global South.
- No single map projection is ideal for every purpose. The appropriate choice depends on whether the map is being used for navigation, statistical analysis, thematic representation, general reference or polar studies.
Which Projection Should Be Used?
The choice of projection should be guided by the purpose of the map:
- Navigation and Direction: Conformal projections such as the Mercator projection are useful because they preserve angles and local shapes, helping with navigation and route plotting.
- Thematic and Statistical Mapping: Equal area projections, such as Equal Earth, are better suited to comparing variables such as population density, climate and land cover because they maintain relative area.
- General Reference Maps: Compromise projections such as Robinson and Winkel Tripel seek to balance distortions in shape, area and distance, producing a visually balanced representation of the world.
- Polar and Single Point Studies: Azimuthal or planar projections are particularly useful for representing polar regions and analysing distances or routes from a central point.
Key Concepts
- Mercator Projection: A conformal cylindrical projection that preserves angles but significantly distorts area, particularly towards the poles.
- Equal Earth Projection: An equal-area projection that maintains the relative proportions of land areas.
- Robinson Projection: A compromise projection designed to balance distortions in area, shape and distance for general world maps.
- Winkel Tripel Projection: A compromise projection that seeks to minimise overall distortions of area, distance and direction.
- Map Projection: A mathematical method of transforming Earth’s curved surface onto a flat map.
Way Forward
Map projections should always be selected according to their intended purpose. Educational and official maps should increasingly use projections that minimise unnecessary distortion and help users develop a more accurate and balanced understanding of geographical space.