In order to make RDF data more accessible to users, we have developed the visual tool VisGraph^3. It allows you to read, create, and modify RDF graphs.
In this demo, we present a web-based prototype that support Read-Write aspect of the Web. In contrast to related work, RDF triples can be created and shared entirely
with visual elements.
Introduction
RDF is not only the backbone of the Semantic Web and Linked Data, but it is
increasingly used in many areas e.g. social web,
government, publications, life sciences, user-generated content, media. As a consequence, more and more people come into contact with knowledge representation and
become an RDF provider as well as RDF consumer. The purpose of data visualization is to propose intuitive ways for information perception and manipulation, especially
for those who are not an expert. RDF visualizations can help in this regard by assisting in the exploration and creation of RDF data.
In order to provide a more intuitive and user-oriented RDF visualization, we developed the VisGraph^3. In this demo, we present a web-based prototype for read
and write RDF. The paper is constructed according to sections. In Section , we present implementation and overview of our tool.
Section is devoted to brief related work. The paper ends with conclusions and future work.
Implementation and Overview of VisGraph^3
VisGraph^3 is implemented on top of several open source tools and libraries. To build a basic user interface we used Bootstrap v4.0.0-alpha.6
widgets. Our tool is designed with RWD principles so we can view it in various device and displays.
In VisGraph^3, interaction with the user provides JavaScript and jQuery. The RDF graph visualization is based on
D3, which is a JavaScript library for making dynamic, interactive data visualizations in web browsers.
The back-end is implemented in PHP and MySQL. The source code is available on
https://github.com/visgraph3/demo. Our tool is released under the MIT license.
VisGraph^3 is a web-based application for read and write RDF. The user interface consists of two parts:
the upload page
and the viewer page.
In the upload page users can specify an RDF file in two different ways: by entering a URL or by upload to the server. This part is presented in .
Here we show the last ten projects. VisGraph^3 can load RDF files in Notation3, Turtle, N-Triples and RDF/XML syntaxes.
Upload page
The second page is the viewer page, which is the main part of our web application. This part is divided into two areas: the control area and the graph area.
In the control area users can add prefixes and IRIs that makes it easy to enter long IRIs. Here we can filter predicates, which are available in the loaded file.
An RDF graph is seen in the graph area. We visualize an RDF graph as a node and directed-arc diagram, in which each triple is represented as a node-arc-node edge
This part is presented in . The indication on the node displays a pop-up window, where we can add a subject, a predicate or an object.
After editing user can download an RDF graph in Turtle or RDF/XML syntax. It is also possible to save and share an RDF graph in the server. All share projects
have its own URL.
In this Subsection, we discuss visualization tools, which can be divided into three groups: desktop applications, semi-web applications, and web applications.
The first group relates to native tools running on operating system , , ,
, and . In , authors present Protégé that is ontology editor providing support for
knowledge acquisition. This application allows the interactive creation and visualization of classes in a hierarchical view. Isaviz is
a visual environment for browsing and editing RDF models represented as directed graphs. It supports various RDF serializations and based on the GraphViz
library. In , OntoTrack is presented. It is another an ontology authoring tool that provides an animated and zoomable
view. OntoViz Tab is another application based on the GraphViz library. It shows ontologies in Protégé as 2D graph with
the capability for each class to present, apart from the name, its properties, and inheritance and role relations. Yet another Protégé plug-in is
ProtégéVOWL . It provides a comparatively intuitive and usable ontology visualization. ProtégéVOWL consists of the viewer for ontology
presentation, a sidebar for element details, and a control panel for configuration.
The second group is a semi-web applications Haystack , and ,
which require both the local environment and the web, e.g. are extensions to web browsers. In , authors show Haystack, which is
a personalized information repository that supports RDF. Another application is Tabulator , which recognizes and follows RDF links to
other RDF resources based on the user's exploration and analysis. Openlink Structured Data Sniffer is the next tool that is an extension for
the Chrome, Firefox and other browsers. It detects and presents RDF data embedded in web pages and serialized in JSON-LD, RDFa, Turtle and other serializations.
The third group relates to web based applications , , ,
and . In , Linked Data Vizualization Wizard (LDVizWiz) is presented. It provides a
semi-automatic way for the generation of visualization for RDF data sets. LDVizWiz can catalog data in one of the following classes: Temporal, Geography, Event, Agent,
Organization, Knowledge and Statistics. Another web application is rdf:SynopsViz that is a tool for hierarchical charting and visual
exploration of Linked Open Data (LOD). It provides some statistics about data sets, e.g. number of triples, properties, classes etc. The next tool is
Sgvizler . It is a JavaScript library which visualize of SPARQL result sets. Sgvizler users can specify the query, the type of
visualization to generate, the dimensions of the chart etc. In , authors show WebVOWL. This tool is similar to ProtégéVOWL and provides
an ontology visualization. Yet another web tool is OpenLink RDF Editor that enables editing of RDF documents in Turtle serialization.
Future Work
In this paper, we have presented VisGraph^3, a web tool for RDF visualization and creation. The tool does not require prior knowledge of RDF syntaxes.
Some future extensions of our tool include support of new serializations,
especially syntaxes that handling named graphs, and deal with the large amount of RDF data. We would like to add more options for filtering, e.g. selection of a node and
its neighbors. The desired function is also authentication to the user profile, where the individual projects are stored. In can be done with
Solid is a set of conventions for building decentralized social applications.
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