PostGIS + Python — Query & Indexing Workflows

Production-grade spatial database engineering for backend developers, GIS admins, and platform teams.

🌐 www.postgis-python.com

A free, in-depth documentation site covering the full stack of building fast, reliable spatial systems with PostGIS and Python — from bounding-box pre-filters and KNN distance operators to GiST index architecture, ORM integration, live schema migrations, and production performance monitoring. Every pattern pairs runnable PostGIS SQL with real psycopg / SQLAlchemy 2.0 / GeoAlchemy2 / Shapely integration code — no pseudocode.

Why this site

Spatial workloads rarely fail from a single missing index. They fail from misaligned index architecture, query-planner misestimates, and driver-level translation issues that only show up under load. These guides bridge the gap between PostGIS internals and Python application patterns, with EXPLAIN-plan walkthroughs, explicit SRID handling, and copy-paste-ready implementations validated against production-shaped workloads.

What's covered

• Core Spatial Query Patterns — bounding-box filtering with the && operator, ST_DWithin radius searches, KNN <-> nearest-neighbor queries, and spatial joins.
• Advanced GiST Indexing & Optimization — partial and composite indexes, index-only scans, EXPLAIN (ANALYZE, BUFFERS) interpretation, and choosing between GiST, SP-GiST, and BRIN.
• SQLAlchemy & GeoAlchemy2 Integration — model mapping, session management, hybrid geometry properties, type coercion / serialization, driver selection, and async streaming.
• Spatial Schema Migrations & Evolution — adding geometry columns to live tables, in-place SRID reprojection, concurrent index builds, and zero-downtime backfills.
• Spatial Performance Monitoring & Observability — pg_stat_statements for spatial hotspots, GiST index bloat detection, and autovacuum tuning for geometry-heavy tables.

Tech stack

• Eleventy static site generator (Nunjucks + Markdown)
• Hand-authored, theme-adaptive inline SVG diagrams
• Structured data (JSON-LD), accessible (WCAG 2 A/AA) markup, and a PWA service worker
• Deployed on Cloudflare Workers (Static Assets)

Local development

npm install
npm start          # local dev server with live reload
npm run build      # build to _site/
npm run deploy     # build + deploy to Cloudflare Workers

Contributing

Spotted an error, an outdated PostGIS/Python idiom, or a pattern worth adding? Issues and pull requests are welcome.

License

Content and code © the PostGIS + Python project. See the repository for details.