Aplicación de Base de Datos en Visual Fox Pro 9.0©

An initial version of this ontology is published at the URL http://purl.org/viso/ to document it and share it for the discussion within the community. A detailed documentation of each ontology module is automatically generated using the LODE ontology-documentation tool12 and includes a description of each ontology term, its related terms, and depictions. However, the ontology and its documentation are not meant to be in a final state, but to be a basis for ongoing discussion. We can only benefit from the aspect of a shared ontology, if it is broadly used and accepted by the community. Therefore, we created a web-platform with rich communication and voting abilities to allow for discussing each ontological term. The platform, which is tightly integrated with the ontology documentation, allows for both ranking existing definitions and proposing new interpretations. Because the ontological terms can only be effectively discussed if the original literature sources are available, we further extended the documentation to show examples as well as quotations and literature references for each resource (Fig. 5.16). Since quotations, references, and authors are modelled in RDF as well, they can be conveniently queried using SPARQL, e. g., to find out which terms a specific author has influenced.

Figure 5.16: Excerpt of the VISO documentation showing the term Composite Graphic Object. Quotations from literature are given as annotations. Each term can be commented and discussed.

Chapter 6

A VISO-Based Abstract Visual

Model – AVM

The Abstract Visual Model (AVM) abstracts from concrete platform dependent models such as HTML or X3D. It can be seen as a platform-independent model (PIM) in the sense of the Model Driven Architecture1 (MDA). In contrast to scenegraphs, which focus on offering a model for rendering the geometry of a scene, including logical and physical constraints, the AVM offers a model for information visualisation graphics that explicitly stores the graphic relations of graphic objects. This allows for using the AVM for calculations concerning (additional) valid mappings. Concrete positioning in space is only stated, if information is directly mapped on position in a graphical space. This also means that no layout information is stored and tools interpreting the AVM have to use layout algorithms. The model does not necessarily form a tree structure, but may form an arbitrary graph. The AVM is made up from terms of the VISO. It is an RDF model with instances of type viso-graphic:GraphicObject, related to each other via viso-graphic:GraphicObjectToObjectRelations in order to form visual structures. Each viso-graphic:GraphicObject may also have a set of viso-graphic:GraphicAttributes attached defining properties of the object in the graphic space such as position or colour. Fig. 6.1 shows an example of an abstract visual model of two graphic objects being visually linked to each other, each graphic object representing a resource in the (domain) RDF model.

In the remainder of this chapter, we have a closer look at the »building blocks« of the AVM – graphic objects, graphic attributes and other graphic relations. Furthermore, we introduce a role-based approach to compose graphics on a fine-grained level, describe composition classes based on these roles and give examples of AVM models. Finally, we discuss why there is the necessity for an additional abstraction like the AVM.

6.1

Graphical Notation Used in this Chapter

Since displaying the whole RDF model of an AVM graphically leads to very crowded and complex diagrams, throughout this chapter, we use a specific graphical notation for AVM, which we developed for illustration purposes. This notation does not scale well to arbitrary models, though. Fig. 6.2 shows the model of Fig. 6.1 using this notation. The pentagons represent graphics objects, labeled with their shapes (circle, line). Rhombs stand for relationships; played roles are represented as rounded rectangles. The AVM could be seen as a further application of the Object Role Model (ORM) of Halpin [Hal01]. Consequently, the graphical notation of ORM [Hal05] may be a candidate notation to substitute the notation that we use in this

CHAPTER 6. A VISO-BASED ABSTRACT VISUAL MODEL – AVM I :GO1 I :LinkingRel1 vg:linked_with I :GO2 I :GO3 vg:linked_with I vg:Line vg:shape_named vg:linking_node vg:linking_node vg:linking_connector I vg:Circle vg:shape_named vg:shape_named avm:represents I ex:PersonB I ex:PersonA avm:represents avm:repre- sents ex:knows P

Figure 6.1: Example of an Abstract Visual Model (AVM) describing a complex graphic object with con- cepts and relations defined in the VISO/graphic ontology: The graphic relation viso-graphic:linked_with is used to relate various instances of viso-graphic:Graphic_Object. Notation: I for instance, P for property, cf. legend in .

Figure 6.2: The same AVM as shown in Fig. 6.1 using a graphical role notation (hiding some information such as links to the represented resources). In the upper left corner a concrete graphic implementing the model is shown.