Damn Cool Algorithms: Quadtrees and Hilbert Curves
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Submission timeline
2007–2026One slot for every year since HN launched. Height is that year's peak points; orange marks a 100+ point or 50+ comment breakout. Select a bar to open its strongest thread.
First comments on top threads
HN comment orderThis might be obvious to many, but spatial indexes are good for more than just "show me the restaurants within five miles of me". It's a good technique to know for efficiently searching any two columns simultaneously. If you have, for example, a database of people, their hometown, and their favorite color, and you want to know all people from Chicago that like green, a spacial index over color and hometown will be vastly more efficient than a "regular" single-column…
Addenda & thoughts since I do a lot of work along similar lines: It's probably not a bad idea to have the option of a spatial index at the leaves of a geohash, as the geohash is necessarily of limited precision and will behave badly if someone inserts 100k points all within a 1x1 foot area. ;) (This is equivalent, roughly, to a plain quadtree only with the first N levels of the tree pre-calculated and cached locally.) I'm guessing…
The first top-level comment from each of the four biggest threads, in HN’s own order. Excerpts are shortened; open a comment for full context.
- Breakout years
- 2
- Total points
- 247
- Total comments
- 24
100+ points or 50+ comments
reference only — not used in Hall rules or ranking
reference only — not used in Hall rules or ranking
Every submission
| Date | Title as submitted | By | Points | Comments |
|---|---|---|---|---|
| 2009-11-09 | Damn Cool Algorithms: Spatial indexing with Quadtrees and Hilbert CurvesFirst breakout | nickjohnson | 107 | 10 |
| 2012-01-18 | Damn Cool Algorithms: Quadtrees and Hilbert CurvesBest thread · Latest 20+ point return | emson | 137 | 14 |
| 2018-08-16 | Damn Cool Algorithms: Spatial Indexing with Quadtrees and Hilbert Curves | dpeck | 3 | 0 |