The resolution is smarter than the headlines, and more revealing about Africa’s geopolicy problem.
Having been one of those who loudly disagreed with the African Union’s decision to anoint one map projection, Equal Earth, before consulting broadly with Africa’s cartographers, geolocation engineers and wider digital community, you can imagine how many friends triumphantly forwarded me news of Friday’s UN vote. 😊
I have now read the actual resolution. Relief. The UN did not quite do what the headlines say it did.
The decisive sentence acknowledges that “no single projection” can perfectly flatten the Earth and that each is suited to particular purposes. Let me quote it in full:
“That no single projection can perfectly represent the curved surface of the Earth on a plane, and that each projection is therefore suited to particular purposes, while noting that the present resolution is particularly concerned with projections that preserve the relative sizes of the world’s regions and the proportional representation of their surface areas, and is without prejudice to the established practice with regard to the use of cartographic material for navigational purposes.”
It then narrows its concern to relative continental area and leaves navigational practice untouched.
Most importantly, Equal Earth is described only as a “relevant option.” The resolution, as with most UN General Assembly operations not confined to the administration of the UN itself, is non-binding. It neither bans Mercator nor abolishes its more ubiquitous modern digital incarnation, Web Mercator. In fact, the official UN account says the General Assembly encouraged wider use of equal-area projections, “particularly” Equal Earth, where comparative size matters.
That is a more technically astute position than the AU’s formal decision, which “ADOPTS” Equal Earth and urges school curricula to follow.
As I argued in my earlier essay, Semafor commentary and X thread back when the AU made its decision, every flat map is an engineered bargain. An orange peel cannot be pressed into a sheet without some stretching, tearing or compressing. You must break some eggs to make an omellete. Area, shape, angle, distance and direction cannot all survive the operation if you want to turn an almost-spherical earth into a flat map. The constraint thus facing every cartographer is never, “Which map is true?” but rather, “Which error can this task tolerate?”
Equal Earth is a clever approach to addressing one historical trade-off: to ensure accurate navigation with the tools available in the 16th Century, flat maps had to compress the sizes of certain places, including Africa, the Caribbean, and many other parts of the Tropics. But it is not an African insurgency against Western geospatial hegemony. It was devised in 2018 by Bojan Šavrič of Esri in California, Tom Patterson of the US National Park Service, and Bernhard Jenny of Monash University. No Africans involved.
Their paper and Esri’s history explain that the design grew out of the Boston schools’ Gall-Peters controversy (where in an attempt to decolonise their curriculum, some school administrators imposed a specific mapping projection), blended traits of Latvia’s Putniņš P4ʹ (developed in 1934) and Germany’s Eckert IV (1906), and focused on visual appeal as well as area-size fidelity. The catchy name and an AU endorsement has catapulted this projection to a level of mass awareness rarely enjoyed by any of the 20-odd projections competing for attention out there.
The media story is equally careless about Mercator. It does not selectively or deliberately “shrink Africa.” The map is the outcome of a very neutral mathematical formulation:
The formulation’s local linear scale is sec φ, and its local area scale is sec² φ. Consequently:
- every place at the same latitude receives exactly the same distortion;
- northern and southern latitudes are treated symmetrically;
- longitude does not affect the amount of area distortion;
- the central meridian
can be moved anywhere;
- there is no Africa parameter, Europe parameter or racial hierarchy hidden in the geometry.
In fact, Mercator is designed not to be overly dependent on its choice of central meridian. It uses zero degrees purely for orientation. It does not require Greenwich, London, Brussels or any other European location to be the central point of reference. Its central meridian is fully adjustable. A Mercator map can be centred on Accra, Jakarta, the Pacific or any other longitude without altering its projection properties. Equal Earth, the AU’s preferred flat-surface mapping system, is more emphatically dependent on the central meridian (historically Greenwich in England) for achieving its size restoration mission.
Mercator does magnify, by sheer mathematical necessity, progressively away from the equator, making Africa and other tropical regions look smaller relative to high latitudes. Parts of Latin America (think Ecuador) and Asia (Indonesia for example) fare even worse.
In return, the classical projection preserves local angles and shapes, which is why it solved a navigational problem in 1569 and why Web Mercator remains the standard substrate for online maps. Web Mercator’s square, self-consistent, quadtree is what makes 256-pixel tiles, zoom levels, and infinite east-west scrolling possible. Equal Earth’s frame is a 2.055:1 lens with curved edges and a pole line 59 per cent the length of the equator. Using it for digital map-rendering leads to dead corners, no seamless wrap, and no natural zoom hierarchy. Its best use is on posters pushing the “correct size” mantra.
Correct area size is, sadly, not always also correct geography. Esri’s documentation admits that Equal Earth distorts shapes, directions, angles and distances and stretches tropical features north-south. On an Africa-centred stress test, Equal Earth makes the continent’s outline about 27 per cent too tall for its width, while roughly half of African land sees angles deformed above 15 degrees.
Mollweide, published in 1805, preserves area size just as well as Equal Earth but cuts the outline error by about nine percentage points and performs much better on angular distortion. McBryde–Thomas FPS2 and Wagner VII also beat Equal Earth on important measures. Even Mercator, useless for comparing continental areas, preserves Africa’s outline proportions far more closely, about 4 per cent off in this test. Which is simply to say that even on the one issue that seemed to matter most to the AU (comparative continental sizes), the continent had better choices than Equal Earth.
The United States’ tone at the UN was needlessly contemptuous, but its “superfluous” complaint had a kernel of truth. Google Maps moved to a 3D globe at low zoom in 2018. Digital cartography can change projection as the user changes purpose. Adaptive mapping systems in the digital realm now allow for “globe” for planetary comparison, “equal-area” when comparing sizes, “conformal” for street-view, and “local coordinate systems” for engineering. At street level, Mercator persists because conformality, tiles and interoperability matter more than how continents look from space or in a school atlas. Geometry, after all, cannot be tamed by political voting at the AU.
This is the Katanomic fracture in brief. Politics loves the large, legible and shiny: “make Africa look big.” Policy lives among small, annoying distinctions: area, angle, scale, centring, zoom, tiles, coordinate reference systems and geodesy.
Africa has again mobilised brilliantly around the WHAT while underinvesting in the HOW.
| The UN resolution rescues the correct principle: use equal-area projections when area matters, and use other projections when other properties matter. So long as we keep that principle in mind, there is no harm done. Mistaking “relevant option” as some in the media are doing to mean “the one true map” is plain misinformation. |