Explorator How to

The Explorator is a tool for exploring RDF data by direct manipulation. Explorator’s visual user interface allows users to explore an RDF database to both gain knowledge and answer specific questions about a domain, through browsing, searching, and exploring.

You can see an Explorator's example of use here.

This document describes the main Explorator’s functionalities and explains how to use them.

Note: The screens shown in this tutorial reflect an older version of Explorator; they will updated soon. Nevertheless, the essential mechanisms and primitives remain the same.

1 Menu
   1.1 Dropdown Menu
     1.1.1 CSS
     1.1.2 All Classes
     1.1.3 All Properties
     1.1.4 Query
     1.1.5 Repository
   1.2 Keyword Search
   1.3 Operations toolbar
     1.3.1 Set of Resources
     1.3.2 Set operations
     1.3.3 Query
2 Facet browsing
3 Interface operations
   3.1 Visualizing subjects, predicates and objects
   3.2 Detailing resources
   3.3 Selecting resources

1 Menu

The menu appears on the top of the Explorator’s window. It carries the dropdown menu, the keyword search, dereferencing search and the operations toolbar.

1.1 Dropdown Menu

The dropdown menu holds a list of Explorator’s functionalities.

1.1.1 CSS

The CSS functionality is used to change the color of Explorator's resources, classes and properties. Clicking on this option shows the following panel:

In this panel, you can write simple css rules. For example, the css rule below turns the color all rdf properties to red:

.property { color:red; }

The name of the css rule must be an RDF class name (Person, Property, Country) to which you want to apply the rule. Ex.: .class, .resource, .country, .lake, .browser, etc.

1.1.2 All Classes

This functionality returns a set of resources that have, at least, one triple with the following structure:

(resource, rdf:type, rdfs:class)

It returns all resources of the type RDFS:Class. All resources colored blue in the interface are RDF Classes.

1.1.3 All Properties

This functionality returns a set of resources that have, at least one triple with the following structure:

(resource, rdf:type, rdf:property)

It returns all properties present the repository. All resources colored green in the interface are RDF Properties.

1.1.4 Query

This functionality allows you to build a query in Explorator.

You build a query by selecting properties (resources in green) and classes (resources in blue) inside a set and clicking on the query widgets.

For example, you select the property "coverage" and click in the widget "Resource" in the query frame.

Two things happen when you click: The query will be build with the property "coverage", and the result will be computed and displayed in the interface.

You can build complex queries such as shown below.

1.1.5 Repository

The Repository option allows you to define which sparql endpoint will be used in the queries.

By clicking in this option, the following frame appears.

You can enable or disable a repository(Sparql Endpoint) whenever you want. A disabled repository is not queried by Explorator.

In that frame, you can also add you own Sparlq Endpoint to Explorator.

TO add a new sparql end point, you must supply a name and the url of your sparql endpoint, and click on the Add button.

1.2 Keyword and Dereferencing Search

You can dereferencing an URI using the text field above. You must use the button 'GO' to execute this operation. You can apply all the others operations over the triples extracted from the URI dereferenced. The triples extracted will be stored in the repository called EXPLORATOR_DEFAULT.

You can search for a known item using the text field above. The keyword will be searched in the subject, predicate and object of all triples in the repository. You must use the button 'search', to start the query.

1.3 Operations toolbar

Using the operation toolbar you can operate on a resource or on sets of resources. In this toolbar, you can find two functionalities: the set operations and the query builder operation.

1.3.1 Set of Resources

You can define a set of resource in two ways:

By selecting the elements individually, as shown in the image below:

Or by selecting the whole set by double-clicking on its corresponding box.

You can select more than one resource or set by keeping the ctrl key (command on Mac) pressed while clicking on the elements or sets.

1.3.2 Set operations

You can compute the intersection, union and difference between two sets of resources.

This is done using a calculator metaphor - click on a resource or set of resources and set is as the first operand; choose the operation by clicking on it, then similarly choose the second operand. Choose the operation and click on the "=" operator to get the result. This is shown below.

As result, you will get the union, intersection or difference between the resources.

1.3.3 Query

You can use the operation SPO to make a query in the database. The SPO operations appears in the toolbar as shown below:

To use this operation, you must set, at least, one (or more as desired) of the parameters S, P or O (select the resource or set and click on the parameter), and click on ‘=’.

2 Facet browsing

You can use the operators “F” and “F*” in the toolbar to facet a set.

Both allow you to facet the set of resources. Once faceted, you can filter the set by the properties of its resources. This mechanism of filtering is called facet browsing.

The function “F” uses a given set of facets to build the facet interface. The function “F*” builds a facet interface using all properties available in the resources of the set.

The facet browsing interface is shown below.

Using the example above, if you click on a facet value “Asia-Pacific” into the facet “Region”, for the SET T in the right, it will exhibit only 2 elements that have the property “Region” as “Asia-Pacific”, as shown below:

3 Interface operations

3.1 Visualizing subjects, predicates and objects

In each set you can find the operations S, P, O.

These operations have a different semantics from the operation SPO that you can find in Explorator’s toolbar.

The S, P and O operators allow you to visualize the subjects, the predicates or the objects of the triples in the corresponding set. Below, you can see an example of the same set of triples displayed in different views. On the left, you have the subject of the triples (clicking on the S operator), on the middle, all predicates in the triples (clicking on the P operator) and on the right all objects (clicking on the O operator).In this way you can have the same set of triples displayed in 3 differents ways.

3.2 Detailing resources

On the interface, you normally see an RDF resource. As shown below:

You can easily inspect the triples where the resource is subject, predicate or object. When visualizing the subject of a triple, you can click in the “+” icon to get the details of this resource, i.e., all triples where it is the subject. Below, we have an example of this functionality. The set on the left shows the resource, and the set on the right shows the triples where the same resource is the subject.

3.3 Selecting resources

Any resource you see in Explorator’s interface may be selected. Below, we show all selectable pieces of information in the interface.

Selecting a whole set:

Selecting one or more resources:

Selecting the properties:

Note that you can select properties in different ways.

Selecting objects:

Note that you can select objects in different ways.

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