Filed under Java

Failed Experiment: Memory Efficient Spatial Hashtable

The Background of my Idea The idea is to use a hash table for points (aka HashMap in Java) and try to implement neighbor searches. First of all you’ll need to understand what a spatial key is. Here you can read the details, but in short it is a binary Geohash where you avoid the memory … Continue reading

Spatial Keys – Memory Efficient Geohashes

When you are operating on geographical data you’ll use latitude and longitude to specify a location somewhere on earth. To look up some associated information or if you want to do neighborhood searches you could create R-trees, quad-trees or similar spatial data structures to make them efficient. Some people are using Geohashes instead because then … Continue reading

Free Online Graph Theory Books and Resources

A link compilation of some Hackernews and Stackoverflow posts and a longish personal investigation. The DaMN book and its companion book Graph Theory with Applications, J.A. Bondy and U.S.R. Murty Graph Theory, Reinhard Diestel Graph Theory Tutorials Digraphs: Theory, Algorithms and Applications, 1st Edition Wikipedia – Graph Algorithms Algorithms and Complexity, Herbert S. Wilf Lecture … Continue reading

Bird’s Eye View on ElasticSearch its Query DSL

I’ve copied the whole post into a gist so that you can simply clone, copy and paste the important stuff and even could contribute easily. Several times per month there pop up questions regarding the query structure on the ElasticSearch user group. Although there are good docs explaining this in depth probably the bird view … Continue reading