Data maps

Best map projection for thematic world maps

For thematic world maps such as population density, climate or election results, use an equal-area projection, ideally Equal Earth. Colour fills the area on the map, so only true areas make a country's visual weight match its real size.

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Equal-area

You want to map data

Best choice: Equal Earth

Equal-area, pseudocylindrical

Why

On a data map colour fills the area, so a big country draws the eye more than a small one. An equal-area projection makes that visual weight match the real area. Equal Earth combines this with readable continent shapes.

Area: preserved
Shape: distorted
Distances: distorted
Angles and directions: distorted
Continuity: preserved

Open in the map lab Projection guide

Also good

MollweideEqual-area
A classic choice for global data and sky maps.
Open in the map lab Projection guide
Interrupted Goode HomolosineEqual-area
Distorts land shapes least, but cuts the oceans, so it suits land data only.
Open in the map lab Projection guide

What to avoid

Mercator

It exaggerates the weight of northern countries such as Canada and Russia and understates countries near the equator.

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Colour weighs as much as area

On a choropleth map each country is filled with one colour. Readers don't add up values; they take in patches of colour, so a large area feels more important. If the projection enlarges the north, data from Canada, Russia or Scandinavia gets an unfair advantage.

That is why thematic world maps use equal-area projections. Projection Wizard, which builds on John P. Snyder's guidelines, proposes equal-area or compromise projections for world maps and advises against conformal ones.

Equal Earth, Mollweide or Goode

Each of these keeps areas true. The choice depends on the shape of the map and on whether your data covers the seas too.

Equal Earth: the default choice, with readable continent shapes and straight parallels.
Mollweide: a classic for global data and sky maps, fitting the world into an ellipse.
Goode's interrupted homolosine: the truest land shapes, but the oceans are cut, so it suits land data only.

When an equal-area map is not enough

An equal-area map shows area honestly, but not the number of people. If a country's size should reflect its population, you need a cartogram, a map that deliberately resizes countries by the data.

A map of one continent or country needs a projection fitted to that area instead, such as a conic or an azimuthal one. Those are not in our map lab yet.

Frequently asked questions

Which projection should I use for population density maps?+

An equal-area one, such as Equal Earth or Mollweide. Density is people per unit of area, so the map has to show areas in their true proportions. Otherwise the sparsely populated north looks more important than it is.

Is Robinson suitable for data maps?+

Robinson is a compromise, so it distorts area a little, most of all near the poles. It is usually fine for overview maps, but when the data is about area, an equal-area projection is the safer choice.

Why does Goode's homolosine cut the oceans?+

Each of its lobes has its own central meridian, and the cuts run through the oceans. The land is less distorted as a result, but marine data such as currents gets chopped up.

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