UPDATE In the first version of this post I have made an error with regard of the retrieval of possible matches. The update has fixed that.

Sometimes I find myself in a situation where I need a very specific data structure with very specific properties. This time I needed something with which I can quickly retrieve nearby elements in 2D space. Although there are data structures perfectly suited to do so, such as a R-Tree, Kd-Tree and other related structures, I needed something which is very easy and somewhat performant to insert into and remove from.

During my journey in implementing the algorithms as described in the paper “High-performance spatiotemporal trajectory matching across heterogeneous data sources” I found a requirement to run linear interpolation on two data sources. In this blog post I describe the most important pieces of logic used for the interpolation or extrapolation of two sets. This code is written using C#, but the algorithm should be fairly easy to port to other languages.

Suicide as a result of depression is a topic I have subtly written more about in the past. This time I specifically want to cover the question whether the act of committing suicide can be deemed good or bad. Have people a right to commit suicide, and how far may relatives go to prevent one from committing suicide? Lately I have been discussing the morality of suicide with a few different people which yielded an interesting viewpoint I want to write some more about.

In the name of prototyping and quick idea validation I have turned to Telegram to validate both the technical, social and emotional sides related to spatiotemporal matching. Telegram is an easy and cheap alternative to building a mobile app for user tracking. Although there is less control over how the data is collected, it is a decent way to test several things out before fully committing to such big project.

In this post I am going to cover the technical aspects of implementing the collection of position information using Telegram. Later on I will write a bit more about the social and emotional aspects that come with fully automatic flight logging over at the Skyhop blog.

Sometimes it’s just easier to deal with a flat grid representing coordinates than to deal with certain cartesian projections. Though I understand that these projections are there for a reason, there are situations where it might be beneficial to have a simple grid representing the number of kilometers from the equator as Y value and the number of kilometers from the Greenwich meridian as X value. Read on for some quick and dirty map projection magic;