One of the most interesting applications I saw at the recent Semantic Technology conference was Freemix. The application, which is currently in limited beta, allows anyone to easily create customized views over data that they upload into the system. There’s also the usual networking features providing an additional social dimension to data sharing and publishing. As I understand it Zepheira have plans for expanding the range of features in all sorts of ways, including new visualisations, the ability to merge and remix data from several sources, and naturally enough a commercial version that can be deployed within the enterprise.

The core of Freemix is Simile Exhibit and a drag and drop interface for building up an Exhibit presentation over data that the user has uploaded. Data can be presented in several different ways, including simple tabular spreadsheets and in the Exhibit JSON format. Exhibit provides a number of different existing views suitable for presenting data, including lists, tables, maps, timelines, etc. As a web developer its straight-forward to build up your own Exhibits; Freemix takes this to the next level, making it trivial to build a presentation in just a few clicks, without the need to learn any markup: you just have to understand your own data.

Naturally enough I was curious to know whether Freemix could be used to build presentations of Linked Data, and specifically whether I could feed it with data from the Talis Platform. I’ve been working with the BBC data quite extensively recently, and have been compiling a space flight dataset. So I thought I’d use those as my test cases. Both of these datasets are in Platform stores, so I explored the options for extracting data using a SPARQL query in order to build a presentation in Freemix. It turns out its really easy.

Freemix supports importing JSON data from a URL, so I knew that in theory I could write a SPARQL query against a Platform store and use the SPARQL protocol request URL as the import target. As I didn’t want to extract the whole dataset, just some interesting subset for my presentation, a SPARQL CONSTRUCT query seemed like the best option. Like Exhibit, Freemix requires a relatively flat data structure — i.e. resources with properties, rather than a true directed graph. This means that within the CONSTRUCT query I would need to simplify the graph structure, removing some of the richer modelling, to re-shape the data to fit Freemix’s expectations.

Here’s a query I came up with for my NASA data:

PREFIX rdfs:
PREFIX dc:
PREFIX space:
PREFIX xsd:
PREFIX foaf: 

CONSTRUCT {
?spacecraft foaf:name ?name;
space:agency ?agency;
space:mass ?mass;
foaf:homepage ?homepage;
space:launched ?launched;
dc:description ?description;
space:discipline ?label.
}
WHERE {
?launch space:launched ?launched.

?spacecraft foaf:name ?name;
space:agency ?agency;
space:mass ?mass;
foaf:homepage ?homepage;
space:launch ?launch;
dc:description ?description;
space:discipline ?discipline.

?discipline rdfs:label ?label.

FILTER (?launched > "2005-01-01"^^xsd:date)
}

The query finds all spacecraft launched since 2005, extracting the name, agency, mass, etc. The labels of the disciplines (subject categories) and the launch dates which are originally associated with separate resources in the underlying graph, are re-presented here as properties of the spacecraft itself. Not ideal in a modelling or data interchange perspective, but a reasonable trade-off for shaping data for presentation purposes.

So far so good. The Talis Platform supports a range of output options from CONSTRUCT queries including both RDF/XML and RDF/JSON. Unfortunately Freemix doesn't support RDF/JSON as an input option although this would make a nice addition to the range of import options. In order to convert from the RDF/XML to the Exhibit/JSON format for Freemix I used the Talis Morph service. Morph is a simple service that provides a number of options for converting between semantic web formats. RDF/XML to Exhibit/JSON is one of those options, so all I needed to do was pipe the original SPARQL query URL through the morph service to get my final import target for Freemix.

You can view the imported data on my Freemix homepage. And here's a presentation of that same data. As you can see the presentation provides a list and table views, piecharts that break down launches by agency and discipline, and also a timeline view of the launches. This was incredibly quick to put together.

I tried the same approach with some BBC data. So here's a simple Dr Who episode guide as a Freemix. The presentation options are a little more limited here, partly because there aren't as many natural facets to the BBC data, but also because Freemix doesn't (yet?) offer the ability to, e.g. create a coverflow presentation of images, or a tag cloud over blocks of text. The ability to mark fields as numbers and sort tables by multiple fields would also be useful. Having said that, trying searching for "Rose" in the search box to see which episodes descriptions mention her; note that the series facet on the left also automatically updates.

As you can see from the SPARQL query, some massaging of the graph structure was required to include series titles against each episodes.

PREFIX foaf:
PREFIX rdfs:
PREFIX po:
PREFIX dc:
PREFIX freemix: 

CONSTRUCT {

?episode a po:Episode;
foaf:depiction ?depiction;
freemix:seriesTitle ?seriestitle;
dc:title ?title;

po:position ?position;
po:short_synopsis ?syn.
}
WHERE
{
po:series ?series.

?series dc:title ?seriestitle;
po:episode ?episode.

?episode a po:Episode;
foaf:depiction ?depiction;
dc:title ?title;
po:position ?position;
po:short_synopsis ?syn.

}

My only other issue with Freemix is the live-ness of the data. Ideally instead of having to import data directly into the system, it should instead be fetched from source either on demand or on a regular basis. I suspect this is the kind of feature that will end up in a commercial version of the product.

Overall though I was quite pleased with how easy it was to create these kinds of presentations. I'm convinced that for Linked Data to truly hit the mainstream we need simple tools like Freemix that let all of us easily compile and create custom presentations of data. Obviously, we also need to be able to easily select the data that we want to display, and very few people will want to bother with SPARQL queries. So I think there is some interesting work to be done to create SPARQL query builders that tie into browsers, e.g. so I can select the data facets I'm interested in as I browse and then choose to represent those facets in different ways.