GraphHopper Blog

Tricks to Speed up Neighbor Searches of Quadtrees. #geo #spatial #java

In Java land there are at least two quadtree implementations which are not yet optimal, so I though I’ll post some possibilities to tune them. Some of those possibilities are already implemented in my GraphHopper project. Quadtree What is a quadtree? Wikipedia says: “A quadtree is a tree data structure in which each internal node […]

Spatial Keys – Memory Efficient Geohashes

When you are operating on geographical data you can use latitude and longitude to specify a location somewhere on earth. To look up some associated information like we do in GraphHopper for the next street or if you want to do neighborhood searches you could create R-trees, quad-trees or similar spatial data structures to make […]