Simon Willison’s Weblog

Cartographer.js. “Thematic mapping for Google Maps”—which means an easy way of adding heat maps (aka chloropleths), pie charts and point clusters as a layer over a Google map.

Posted 1st November 2009 at 1:20 pm

Recent articles

Claude can write complete Datasette plugins now - 8th October 2025
Vibe engineering - 7th October 2025
OpenAI DevDay 2025 live blog - 6th October 2025

catography 1 chloropleths 1 google 386 google-maps 53 graphs 7 heatmaps 3 infographics 7 mapping 54 maps 43 piecharts 1 visualisation 15

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