software · Picked by us

See how a map changes the shape of the world

Equal Earth

Move a slider between two world maps. See which shapes stretch and which areas stay in proportion.

By Simon Willison

Try the map

Read the making-of

Free; creator's development record

Get the code

Free; Apache 2.0 licence

Free; no sign-in

Simon Willison's Equal Earth map, with a slider and D3 and Natural Earth credits. — A look at the result

What it does

Compare Mercator and Equal Earth on the same map. The views between the two are blends, not equal-area maps.

Who it helps

Teachers, students and anyone curious about maps.

How it was made

Models: GPT · GPT-6 Astra Medium — creator-reported
Tools: ChatGPT Work · AI coding
D3 · Map drawing
Natural Earth · Map data

Simon asked for an animated change between the two projections using D3.
His linked development record names the model and includes the conversation.

What the person did

Simon set the task. The record does not say whether he later edited the code by hand.

What we know

Creator-reported: Model and method come from Simon's development record.

Access checked — 2026-09-20 · Opened the map and selected Equal Earth. The map and control changed to the 100% endpoint. We did not test every map detail.

Can you use it?

Tool and preview: Simon Willison, Apache 2.0. Keep the licence and required notices when reusing the code. Map data: Natural Earth, public domain. Our screenshot is resized; the map itself is unchanged. This feature does not imply the creator's endorsement.

About this project

Picked by Made With Models. Added 2026-09-20. Updated 2026-09-20.

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