Mercator ↔ Equal Earth

Simon Willison used GPT-6 Astra (medium) in ChatGPT Work to build an animated transition between the Mercator and Equal Earth map projections using D3, after the Equal Earth projection was recently voted on at the UN. The tool is available at tools.simonwillison.net/equal-earth.

Tool: Mercator ↔ Equal Earth https://tools.simonwillison.net/equal-earth I got curious about the Equal Earth map projection that was recently voted on at the UN https://www.theguardian.com/world/2026/sep/04/un-vote-world-map-mercator-equal-earth-africa so I had GPT-6 Astra medium in ChatGPT Work build me https://chatgpt.com/share/6a9ee520-c82c-83ea-8111-2f7050c08638 this animated transition between Mercator and Equal Earth using D3. Tags: geospatial https://simonwillison.net/tags/geospatial , d3 https://simonwillison.net/tags/d3 , vibe-coding https://simonwillison.net/tags/vibe-coding , gpt-6-astra https://simonwillison.net/tags/gpt-6-astra