KartoGraphI: Drawing a Map of Linked Data

Abstract

A large number of semantic Web knowledge bases have been developed and published on the Web. To help the user identify the knowledge bases relevant for a given problem, and estimate their usability, we propose a declarative indexing framework and an associated visualization Web application, KartoGraphI. It provides an overview of important characteristics for more than 400 knowledge bases including, for instance, dataset location, SPARQL compatibility level, shared vocabularies, etc.

LDViz: A Tool to Assist the Multidimensional Exploration of SPARQL Endpoints

“…Figure 8 presents a TreeMap graph showing the distribution of different responses obtained while querying 419 SPARQL endpoints obtained from IndeGx [21]. The top level of the TreeMap graph contains seven rectangles each of which covers a Fig.…”

“…To better understand the issues, we further inspected some of the SPARQL endpoints using the KartoGraphi application 11 [21], which provides an overview of the state of the 419 endpoints used in this analysis through the metadata generated by IndeGx. It shows, for instance, that not every SPARQL endpoint is transparent regarding the used vocabularies (only 110 endpoints provide the list of vocabularies used).…”

“…The 419 SPARQL endpoints used in this analysis were obtained from IndeGx [21], a framework designed to index public KGs that are available online through a SPARQL endpoint. The indexing process uses SPARQL queries to either extract the available metadata from a KG or to generate as much metadata as the endpoint allows it.…”

IndeGx: A model and a framework for indexing RDF knowledge graphs with SPARQL-based test suits

“…IndeGx gives access to the metadata it generates during its periodic indexing through a SPARQL endpoint. Additionally, the KartoGraphi [19] website 4 exploits IndeGx to offer various visualizations of the generated metadata, including evolution of this metadata through time.…”

“…To make this output accessible to humans too, we provided, on top of this index service, a visualization Web application called KartoGraphI 8 . It generates an overview of important characteristics and a number of the results presented in this paper can also be visualized and browsed on KartoGraphI [19]. To demonstrate the use of the index in other applications we also provided a demonstrator of a federated query engine exploiting the index.…”