Month: February 2020
Visualizing OSM data in QGIS
Last time we imported OpenStreetMap datasets from Iceland to PostGIS. To quickly visualize our OSM data results, we will now use QGIS to render our datasets and generate some nice maps on the client. Let’s start with our prerequisites: A PostGIS enabled PostgreSQL database preloaded with OpenStreetMap datasets as described in blogpost https://www.cybertec-postgresql.com/en/open-street-map-to-postgis-the-basics/ An up […]
shared_buffers: Looking into the PostgreSQL I/O cache
The PostgreSQL caching system has always been a bit of a miracle to many people and many have asked me during consulting or training sessions: How can I figure out what the PostgreSQL I/O cache really contains? What is in shared buffers and how can one figure out? This post will answer this kind of […]
Migrating from MS SQL to PostgreSQL: Uppercase vs. Lowercase
When migrating from MS SQL to PostgreSQL, one of the first things people notice is that in MS SQL, object names such as tables and columns all appear in uppercase. While that is possible on the PostgreSQL side as well it is not really that common. The question therefore is: How can we rename all […]
How to run a clustering algorithm within PostgreSQL
By Kevin Speyer – In this post, we will cover a step by step guide on how to implement a clustering algorithm within PostgreSQL. The clustering algorithm is the well-known k-means, which splits data into groups by minimising the sum of the squared distances of each point to the corresponding group average. This method belongs […]