Category: Semantic Web, Linked Data and Visualisation

In the context of my diploma and PhD thesis I focussed on the visualisation of data from the Semantic Web with its specific characteristics such as heterogenity and strong semantics.

Posted on

RVL Demo Videos

Have a look at the first two RVL demo videos to learn about the basic principles of the RDFS/OWL Visualization Language (RVL):


RVL – Demo #1 – PropertyMappings and ValueMappings


RVL – Demo #2 – IdentityMappings and Mapping of Value Intervals

Scheduled next videos:

  • RVL – Demo #3 – Using Submappings to Map Connector Attributes
    • Composing mappings based on the role of graphic objects
    • Setting connector width, color, shape
  • RVL – Demo #4 – Labeling and Label Positioning
    • Labeling nodes
    • Labeling connectors
    • Labeling labels
  • RVL – Demo #5 – Mapping to other Graphic Relations
    • While we started with node-link diagrams for simplicity, RVL is not limited to the  graphic relations “Linking”, “Labeling” and “Containment”. On the contrary: a broad palette of alternative graphic relations such as  “Relative Position” (Clustering), “Separation by a Separator” and “Alignment” and  “Adjacency” that are described in the Visualization Ontology (VISO) should follow.
  • RVL – Demo #6 – OWL- and RDFS-specific Mappings
    • Mapping Domain-Range relations between classes
    • Mapping further class level relations  such as universal and existential restrictions
Posted on

Example of a visual mapping described in the RDFS/OWL Visualisation Language (RVL)

RVL is a declarative RDF-based language for specifying visual mappings from RDFS/OWL data to graphic means. In the following we use the language to visualise example data specified using vocabulary from the Citation Ontology:

The above graphic was created by processing the RVL mappings below. A first mapping simply says map cito:cites to directed links
(e.g. connector lines with arrowheads).

@prefix :          <http://purl.org/rvl/example/mapping/> .
@prefix cito:      <http://purl.org/spar/cito/> .
@prefix rvl:       <http://purl.org/rvl/> .
@prefix vg:        <http://purl.org/viso/graphic/> .
@prefix rdf:       <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

:Cites2Linking
      a rvl:PropertyMapping ;
      rvl:sourceProperty cito:cites ;
      rvl:targetObjToObjRelation vg:Linking_Directed_Relation ;
     .

If you move the pointer over the edges, you can observe that also sub-properties of cito:cites have been used in some cases.

Let’s add another mapping to distinguish the different properties by color. We realize this with a sub-mapping attached to the first mapping:

:Cites2Linking
      a rvl:PropertyMapping ;
      rvl:sourceProperty cito:cites ;
      rvl:targetObjToObjRelation vg:Linking_Directed_Relation ;
      rvl:subMapping [
        rvl:subMapping-onRole vg:linking_connector;
        rvl:subMapping-onTriplePart rdf:predicate;
        rvl:subMapping-mapping :PredicateID2Color;
      ].

:PredicateID2Color
      a rvl:PropertyMapping ;
      rvl:sourceProperty rdf:ID ;
      rvl:targetAttribute vg:color_named ;
      rvl:valueMapping [
        rvl:sourceValueOrderedSet (
            cito:confirms cito:cites cito:critiques
        );
        rvl:targetValueList (
            vg:Green vg:Yellow vg:Red
        );
      ].

More examples will follow 🙂

Posted on

VISO now at GitHub

Since there were several requests for reusing the VISO ontology, we decided to move it to GitHub. A lean core version of VISO is currently build from the existing version and a few modules are already available. The existing version will remain for documentation purposes and serve as a base for the new version, which will start with a small set of stable concepts. Concepts that are required by VISO users are migrated incrementally.

If you decide to fork VISO, please use a sorted Turtle notation as it is offered, for example, by TopBraid Composer (Settings… -> Input/Output) in order to ease later merging of your extensions.

Posted on

RDFS/OWL Visualisation Language (RVL) published

An initial version of the RDFS/OWL Visualisation Language (RVL), which was developed as part of my PhD thesis has been published at the HSWI13 (Workshop on Human-Semantic Web Interaction). The slides can be found within an internal report and on slideshare (see below).

Download RVL paper (authors version)

 

 

 

Abstract: Information on how to visualize RDF data is stored differently by each visualization tool to date. We propose the RDFS/OWL Visualization Language (RVL), a declarative language for sharing visualization settings as simple as CSS styles. The mapping definitions can be given a URI and shared along with the data to be visualized, they can be composed, extended and reused. The declarative approach has the benefit that this can be done independently of specific platforms. Unlike styling or presentation languages for RDF or pure visualization languages, RVL combines rich visual mapping capabilities with the direct awareness of RDFS/OWL language constructs.

The documentation of RVL can be accessed at http://purl.org/rvl/ (work in progress). Prototypical tooling for language is currently built and will be published on this blog.