Equal-Area vs Compromise Projections: Which One Does Your Map Actually Need?

After the UN General Assembly recommended equal-area projections in September 2026, the obvious conclusion to draw is that equal-area maps are correct and everything else is a mistake. That conclusion is too strong, and acting on it will make some of your maps worse.

The resolution was aimed at a specific failure: general-purpose maps that use a navigation projection and therefore misrepresent how big places are. It was not a claim that area is the only property worth preserving. Here is how to tell which family your map belongs to.

The three families

Every world projection in common use falls into one of three groups, and the group tells you what the map can be trusted about.

Equal-area (equivalent). Area is exact everywhere. Shape is sacrificed. Examples: Equal Earth, Eckert IV, Mollweide, Gall-Peters.

Conformal. Local shape and angle are exact. Area is sacrificed, badly. Example: Mercator. There is essentially one that matters for world maps, and it is a navigation tool.

Compromise. Nothing is exact, everything is close. Examples: Natural Earth, Robinson, Winkel Tripel, Miller. These are designed by eye to look right rather than to satisfy a constraint.

Note where the UN’s own cartographers sit. The Secretariat has historically used Robinson, Winkel Tripel and Eckert IV, so two of its three habitual projections are compromise projections, not equal-area ones. The resolution recommends a direction to the world; it did not audit the UN’s own back catalogue.

The one question that decides it

Will a reader compare the size of two shaded regions and draw a conclusion from the comparison?

If yes, use equal-area. If no, a compromise projection is usually the better map.

That is genuinely most of the decision. The rest is refinement.

Use equal-area when

• The value is per unit of ground. Population density, land use, forest cover, emissions per square kilometre. The reader is doing area arithmetic whether they know it or not.
• The map is teaching. This is the case the resolution names. A map in front of a student who has no way to correct for the projection should not be quietly making a size argument.
• Size is the point. Territory held, area burned, coverage gained, land under some designation.
• Someone will screenshot it into an argument. If the map is going to be passed around detached from your caption, it needs to survive without one.

Use a compromise projection when

• The map is categorical, not quantitative. Countries you have visited, offices you operate, members of an alliance. Nobody reads relative area off a map like that, and Natural Earth will look better than Equal Earth doing it.
• Recognisability matters more than measurement. A slide, a header image, a poster. Compromise projections keep coastlines looking like the coastlines people have memorised.
• The map is regional. Over a single country or continent, the difference between projection families shrinks a great deal, and other properties start to dominate the choice.

Use Mercator when

Navigation, and layouts that must line up with web map tiles. That is the list. The UN text carves out exactly this case and no more.

Quick reference

The cheapest way to decide

Do not decide up front. Build the map in Natural Earth, which is the default, then switch the projection once the data and colours are in place. Switching re-renders the same document: your regions, labels, legend and imported values all survive it.

Then look at the result and ask whether the map is making a claim about size. If it is, keep Equal Earth. If it is not, keep the one that looks better. Ten seconds of clicking beats a paragraph of theory, including this one.

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Related reading: What is the Equal Earth projection? and the full walkthrough of every projection in the editor, Which map projection should you use?.