Visualizing RDF

I see nodes and edges...

I recently did a review of options for creating visual representations of RDF data. I didn’t just want a general visualization tool, but something that understood RDF enough to represent class instances and literal values differently. I will emphasize instances because several tools out there can read RDF schema or ontologies and create a visualization of classes and their relationships and potential properties, but I want to see instances with their property values.

Triples about existing triples

The easy way and the hard way.

Several years ago in the blog post RDF* and SPARQL* I described how I had played with implementations of the new reification syntax that Olaf Hartig and Bryan Thompson proposed in their paper Foundations of an Alternative Approach to Reification in RDF. I found the new syntax to be straightforward and useful. As you can see from the recent W3C Community Group Report RDF-star and SPARQL-star, this syntax has progressed—with a more search-engine-friendly spelling of the spec’s name—closer to…

Querying for labels

The normal way and the wikibase:label service way

In my last blog entry I discussed various ways that different RDF datasets assign human-readable labels to resources, with the rdfs:label property being at the center of them all. I mentioned how schema.org doesn’t use rdfs:label but its own equivalent of that, schema:name, which its schema declares as a subproperty of rdfs:label. Since I wrote that, Fan Li pointed out that Facebook’s Open Graph protocol also has their own equivalent: og:title, which you can see used in the HTML…

Human-readable names in RDF

Sometimes simple, sometimes not.

First, reviewing some basics before I discuss the edge cases: resources in RDF are represented by URIs, and the spelling of a given URI often provides no clues about what the URI represents. For example, you wouldn’t know from looking at http://www.wikidata.org/entity/Q144 that it represents “dog” as a Wikipedia topic. (We’ll see below that this is a for a good reason.)