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

Introducing gisthost.github.io - 1st January 2026
2025: The year in LLMs - 31st December 2025
How Rob Pike got spammed with an AI slop "act of kindness" - 26th December 2025

catography 1 chloropleths 1 google 394 google-maps 53 graphs 7 heatmaps 3 infographics 7 mapping 54 maps 43 piecharts 1 visualisation 15

Monthly briefing

Sponsor me for $10/month and get a curated email digest of the month's most important LLM developments.

Pay me to send you less!

Sponsor & subscribe