Much of the original point of the web was not just linking from one page to another but also saving and managing links, ideally with some metadata. Because of this, all browsers give you some way to save a link to a web page as a bookmark, and they typically let you sort these into a hierarchical arrangement of folders.

I have usually assumed that people reading this blog already know what RDF is. After recent discussions with people coming to RDF from the Linked (Open) Data and Knowledge Graph worlds, I realized that it would be useful to have a simple explanation that I could point to. This builds on material from the first three minutes of my video SPARQL in 11 Minutes.

When I saw “Add support for scripting languages other than JavaScript” in the Jena release 4.0.0 release notes my first reaction was “What? I can run the arq command line SPARQL processor and call my own functions that I wrote in JavaScript?”

On page 5 of my book Learning SPARQL I described how the open source RDF processing framework Apache Jena includes command line utilities called arq and sparql that let you run SPARQL queries with a simple command line like this:

Over a year ago, in Querying geospatial data with SPARQL: Part 1, I described my dream of pulling geospatial data down from Open Street Map, loading it into a local triplestore, and then querying it with queries that conformed to the GeoSPARQL standard. At the time, I tried several triplestores and data sources and never quite got there. When I tried it recently with Ontotext’s free version of GraphDB, it all turned out to be quite easy.

I recently needed to join two datasets at work, cross-referencing one property in a spreadsheet with another in a JSON file. I used a combination of jq, perl, sort, uniq, and… I won’t go into details.

Something that happens to me now and then: I’ll hear that an organization with a lot of interesting data (science, music, whatever) makes the data available on a SPARQL endpoint. I send my browser to the URL listed as the SPARQL endpoint and I see a web form. I enter a simple query on the web form to retrieve a few random triples, click the form’s button, and the results of my query appear. Then I enter fancier queries to explore the endpoint’s data.