~/talk

10 Things I've Learnt About PostGIS

Talkat FOSS4G SotM Oceania 2018 · 2018-11-20..11-23· [databases]
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Spatial indices cut query time dramatically so adding indexes and using them properly is the first win. ST_Subdivide turns one huge polygon vs 1.1 million lidar grid squares from ~2 minutes to ~0.33 seconds. Centroiding 300,000 building outlines runs in ~3 seconds in PostGIS versus ~23 seconds elsewhere. Store reusable functions for suburb assignment using ST_DWithin ST_Intersects and area rules, enforce geometry types and no-overlap checks, and use normalize_geometry and the pgAdmin4 geometry viewer for debugging.

AI-written summary · about

  1. 0:00Introduction
  2. 0:45Spatial indices as assets
  3. 2:09Speed gains from spatial indexing
  4. 3:40Optimizing slow queries with ST_Subdivide
  5. 5:08Consistency in spatial analysis
  6. 6:34Reusable spatial functions
  7. 8:42Geometry type constraints
  8. 10:48Open-source PostGIS tools
  9. 12:15PgAdmin geometry viewer
  10. 13:19Enjoying spatial problem-solving
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