Quadtrees are everywhere spatial data exists. Mapping services use quadtree-like tile pyramids to serve map tiles at different zoom levels (Bing's quadkey system, for example, addresses tiles as base-4 paths). Game engines use them for collision detection and visibility culling. Geographic information systems use spatial indexes to store and query spatial datasets. PostGIS uses GiST indexes (R-tree-style) for spatial queries on geometries, while PostgreSQL's core supports quadtree-like SP-GiST indexes for certain data types like points.
A spokesman for the Covid inquiry said: "The inquiry is unlike any previous public inquiry. It was given a very broad scope because it is investigating multiple aspects of a pandemic that affected everyone in society."
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NYT Connections hints today: Clues, answers for February 27, 2026