Schímatos: A SHACL-Based Web-Form Generator for Knowledge Graph Editing

Abstract

Knowledge graph creation and maintenance is difficult for naive users. One barrier is the paucity of user friendly publishing tools that separate schema modeling from instance data creation. The Shapes Constraint Language (SHACL)[12], a W3C standard for validating RDF based knowledge graphs, can help. SHACL enables domain relevant structure, expressed as a set of shapes, to constrain knowledge graphs. This paper introduces Schimatos, a form based Web application with which users can create and edit RDF data constrained and validated by shapes. Forms themselves are generated from, and stored as, shapes. In addition, Schimatos, can be used to edit shapes, and hence forms. Thus, Schimatos enables end-users to create and edit complex graphs abstracted in an easy-to-use custom graphical user interface with validation procedures to mitigate the risk of errors. This paper presents the architecture of Schimatos, defines the algorithm that builds Web forms from shape graphs, and details the workflows for SHACL creation and data-entry. Schimatos is illustrated by application to Wikidata.