The fundamental challenge in cartography is converting the Earth’s three-dimensional spherical surface onto a flat, two-dimensional plane. This process, known as map projection, is mathematically impossible without introducing some form of error. Every projection must choose which geographical properties to preserve, such as area, shape, distance, or direction, at the expense of distorting the others. Mapmakers employ various projections, each designed as a specific solution to this inherent geometric problem, prioritizing different qualities based on the map’s intended purpose.
Defining the Robinson Projection
The Robinson projection was explicitly created to achieve a favorable visual balance across the entire globe. Developed by American cartographer Arthur H. Robinson in 1963, his primary goal was not mathematical precision but rather to create a map that looked “right” to the average observer, prioritizing aesthetic appeal.
This map is classified as a pseudocylindrical compromise projection because it forgoes preserving any single property perfectly. It is neither equal-area (landmasses are not represented in their true relative sizes) nor conformal (shapes and angles are not preserved). Instead, it minimizes the overall distortion of shape, area, distance, and direction to provide a visually harmonious representation of the world.
The Design Philosophy and Mechanism
Unlike historical projections derived from a single mathematical equation, the Robinson projection was developed through an empirical, trial-and-error process. Robinson used a graphic design approach, iteratively adjusting coordinates until the map achieved the desired visual harmony. The final construction relies on precomputed coordinate tables that define the map’s grid, with intermediate locations calculated using interpolation.
The map grid, or graticule, is characterized by its specific arrangement of latitude and longitude lines. All lines of latitude (parallels) are straight, parallel horizontal lines, but their vertical spacing is not uniform. Robinson manually adjusted this spacing to control scale and distortion away from the equator.
The lines of longitude (meridians) give the map its distinctive rounded, oval appearance. While the central meridian is a straight vertical line, all other meridians are gently curved, concave toward the center. These curved meridians are spaced equally along the parallels but do not intersect them at right angles, except along the central meridian. This combination classifies it as a pseudocylindrical projection.
Understanding Distortion Trade-Offs
As a compromise projection, the Robinson map features a moderate level of distortion deliberately distributed across the surface. Areas closest to the equator and the central meridian exhibit the lowest error, where shapes and relative sizes appear accurate. Distortion steadily increases as the distance from this central region grows, but this gradual increase prevents the extreme errors seen in projections that preserve only one property (e.g., Mercator’s polar area distortion).
The most significant distortion occurs at the highest latitudes, near the North and South Poles. On a globe, the poles are single points, but the Robinson projection renders them as long, straight lines. The length of these pole lines is fixed, measuring approximately 0.5322 times the length of the equator on the map.
This stretching severely distorts the shapes of landmasses like Greenland and Antarctica, causing them to appear squashed horizontally. However, this shape distortion helps keep area exaggeration in check, making the visual representation of size less misleading than in other popular projections.
Why Robinson Became So Popular
The success of the Robinson projection stems from its deliberate design to be aesthetically pleasing and visually intuitive for a general audience. The map’s smooth, elliptical boundaries and gentle curvature of its meridians avoid the harsh, boxy look or extreme polar magnification found in older projections. This visual fluidity made it a favorite for publishers seeking balanced and natural world maps.
Its widespread acceptance solidified when the National Geographic Society (NGS) adopted it for general-purpose world maps in 1988. For a decade, the Robinson projection became a standard reference, influencing how a generation perceived world geography. Although the NGS switched to the Winkel Tripel projection in 1998, the Robinson remains a common choice in educational materials and thematic mapping due to its ability to convey global spatial relationships effectively.