skills/cartography-geoviz/references/authoritative-sources.md

# Authoritative sources

- Last verified: 2026-07-19
- Review cadence: every 6 months
- Refresh triggers: GeoPandas, Matplotlib, or mapclassify major release; accessibility guidance change

## Canonical sources

- [GeoPandas mapping guide](https://geopandas.org/en/stable/docs/user_guide/mapping.html) — plotting, legends, and classification integration.
- [Matplotlib colormap guidance](https://matplotlib.org/stable/users/explain/colors/colormaps.html) — perceptual ordering and colormap selection.
- [ColorBrewer](https://colorbrewer2.org/) — primary qualitative, sequential, and diverging palette guidance.

Use sources to confirm version-sensitive API details. Keep classification, projection, accessibility, and comparison decisions explicit even when a library supplies defaults.