Graph visualization to help graph query formulation

Graph data structure has proven to be a universal and expressive scientific data representation method. While traditional databases and spreadsheets have a range of tabular viewers and editors, software handling graph views is not so common. We developed LODmilla as a visual frontend for SPARQL endpoints or RDF stores. LODmilla is more than ten years old now, but it still has unique features, such as inline editing data and edges in the graph. LODmilla not only supports on-demand browsing of the graph by expanding and collapsing nodes, but it adds graph-specific operations to navigate in the graph, such as finding routes between nodes or searching limited to the neighborhood of a node.

Often, we need to familiarize ourselves with a large graph, to get an overview of its content, and also to be able to write queries (for example in SPARQL). To ease such tasks, we offer SPARQL Query Helper as a web service, which presents visual overviews of graphs generated via a SPARQL endpoint. Furthermore, it can draw several of these graph overviews and find common classes used in more graphs. LLM support is also available to suggest classes with similar meaning (e.g. Creator class - Author class).