↓Skip to main content
Zeitgeist — a spike by Chris Gathercole
  1. Creators/
  2. Simon Willison — Creator of Datasette; co-creator of Django/

GeoJSON Map Viewer

Blog · Watch/Read · (gathered 2026-09-03)

  • Simon Willison developed a “GeoJSON Map Viewer” tool, highlighting how advanced LLMs like GPT-5.6-Sol can proactively build functional applications and ChatGPT Work can efficiently source complex geospatial data from government sources.
  • The tool allows users to paste GeoJSON objects (Feature, FeatureCollection, or Geometry) and visualize them on an interactive OpenStreetMap with customizable styling, fulfilling a need to display and export local political boundaries.
  • The development process involved GPT-5.6-Sol for initial tool generation and subsequent iterations with Claude Code for web and Fable 5.1, demonstrating a multi-LLM workflow for software creation.
  • LLMs are increasingly capable of not just generating code but also acting as comprehensive assistants for both tool development and the extraction of specific, complex data (like exact political boundaries) from disparate sources.