Load and explore the Pirates data

We assume ClioPatria is still running and you are logged on, either as admin or as a another user with at least read and write access. The initial set of data is added to the library as part of the pirates packages and can be loaded using Repository/Load from library. Then select "pirates -- Piracy data" and click load.

Explore the data

The main entry point for exploring the data is the menu Places/graphs, which lists the datasets loaded into ClioPatria. Select the topmost graph, which holds the piracy data. The two most useful entry points are

1. predicates, which lists all relations in the graph
2. classes, which lists the types that are used in the graph

Note that RDF resources are web addresses, i.e., typically strings of the form http://<host><path>[#fragment]. Many RDF tools and languages allow for an abbreviated notation by declaring a mnemonic that represents the (long) common prefix of RDF resources. For example, the short form for http://semanticweb.cs.vu.nl/2009/11/sem/hasPlace is

sem:hasPlace

We defined prefixes for some commonly used resources in the file config-enabled/pirates.pl that is part of the pirates package. Prefixes are sometimes also referred to as namespaces. See also rdf_register_ns/2 and rdf_current_ns/2.

The Web of Data

As you browse through the data, some links colored red. These are resources that are not defined in the currently loaded dataset. Clicking on such a link opens a page with information on where the resource is used and the button Query the Linked Data cloud. Clicking this button causes ClioPatria to retrieve the information from the resource itself. In the ideal world, the resource (URI) points to an RDF document that provides additional information about this resource. Similar to links in HTML documents, the target may not exist, might not be a valid RDF document, etc.

Exercises

Use the ClioPatria browser (starting from Places/graphs) and answer the following questions:

1. What is the full resource and what is the meaning (according to its comment) of the predicate geonames_ont:featureClass?
2. Piracy actions are modelled using sem (Simple Event Model). Use the ClioPatria browser to find the main types and predicates that make up this model and draw a diagram that explains the main relations.
3. sem:ActorType (the victim ship) and sem:EventType (what happened) are organised in hierarchies. Draw a diagram that explains how the actorType hierarchy is organised.
4. sem:subTypeOf is related to rdfs:subClassOf. Which relation is defined between these two properties? What is the consequence of this for instances of the classes sem:ActorType and sem:EventType.

You are now ready to query pirate data with Prolog.

See also

- Tutorial index