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

How I found the Googloson and why it has negative Energy

I have finally found the Googloson with my self-made Small Googtron Collidor (SGC) – I even had the time to make a photo of it to show you that it is not a fake (see below). Everyone will say I’ve gimped that, but no, I didn’t. Really. I have developed a theoretical proof of the existence of … Continue reading

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 … 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

Rage Against the Android #eclipse

Developing Android applications on Linux with Eclipse sometimes can get really ugly. Sadly neither NetBeans which has a really nice Android plugin, but cannot execute a single test nor IDEA can rescue me or make me switching :( but probably they wouldn’t rescue me due to problems of Android development kit itself – I’m not … 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