ViziQuer: Visually Explore and Query Knowledge Graphs - Visualize the data schema. - Graphically create rich data analysis queries. - Explore and query DBPedia and other RDF Data Sets. - Run schema and query environment over your own data set.
About	ViziQuer allows visualizing a schema of a knowledge graph (RDF data set) and creating rich schema-backed visual queries over the data. Visual presentation of existing SPARQL queries is supported, as well. The schema visualization and visual query support can be done in presence of a pre-loaded data schema. ViziQuer Playground has a rich set of Linked Open Data schemas preloaded to experiment with. Local tool setup as a ViziQuer Tools docker container, or as a ViziQuer local installation allows loading data schemas of the interest for the user. ViziQuer wiki explains the tool and notation usage.
ViziQuer Playground	Open viziquer.app. Register (sign up) as a new user (email checking not done, any e-mail-like string is accepted), then log in and start creating projects and diagrams (example projects are available for exploration). Public diagram allows exploring the visual queries and creating SPARQL query visualizations without log in requirement (see also public diagram description).
Highlights	What is in Your Knowledge Graph? (Research project, supported by Latvian Science Council) Environment and Library of 24 prominent Linked Open Data schemas The paper: Lāce, L., Romāne-Ritmane, A., Grasmanis, M., Sproģis, A., Ovčiņņikova, J., Bojārs, U. and Čerāns, K. Visual Presentation and Summarization of Linked Data Schemas. Knowledge Graphs and Semantic Web. Proc. of KGSWC 2024, Springer LNCS, Vol.15459, pp.290-305. Download the author manuscript A related poster presented at GOBLIN COST Action MC meeting in February 2025 A method and library for Visual Data Schemas (Demo at ESWC'2024). Data schema visualization examples and schema showcase video available. Schema extraction and visualization pipeline explained, as well. Experience with Visual SPARQL Queries over DBPedia (Presentation and paper at VOILA!'2022) Towards Visual Queries over Wikidata (Demo at ESWC'2022) Visual Queries in Distributed Knowledge Graphs (Research project, supported by Latvian Science Council)
ViziQuer Tool Suite	ViziQuer Tools - a collection of docker containers for easy setup of core ViziQuer tool system (ViziQuer, Data Shape Server, supporting database systems) Viziquer - web based environment for visual data schema and query creation Data Shape Server - manager service for stored data schemas, provides the schema and individual entity context information (e.g., for query auto-completion) to the visual tool Data Schema Extractor - extracts the data schema from a custom SPARQL endpoint, produces a .json - structured data schema file (NB! Use "version 2" to obtain schemas compatible with ViziQuer tools) Data Schema Import Service - a utility for importing the data schemas into the Data Shape Server database.
Contact	Contact viziquer@lumii.lv for support, inquiries and any other ViziQuer-related matter. Team leader e-mail karlis.cerans@lumii.lv
Core team	Prof. Kārlis Čerāns (current team leader) Dr. Lelde Lāce Dr. Jūlija Ovčiņņikova Mikus Grasmanis Dr. Uldis Bojārs Dr. Arturs Sproģis Thanks also to Prof. Guntis Bārzdiņš (early ViziQuer notation supervisor), Dr. Mārtiņš Zviedris (early ViziQuer notation founder) and Dr. Agris Šostaks for their contribution. We work at Institute of Mathematics and Computer Science, University of Latvia
Current Research	Lāce, L., Romāne-Ritmane, A., Grasmanis, M., Sproģis, A., Ovčiņņikova, J., Bojārs, U. and Čerāns, K. Visual Presentation and Summarization of Linked Data Schemas. Knowledge Graphs and Semantic Web. Proc. of KGSWC 2024, Springer LNCS, Vol.15459, pp.290-305. Download the author manuscript Lāce, L., Romāne, A., Fedotova, J., Grasmanis, M. and Čerāns, K. A Method and a Library for Visual Data Schemas. ESWC 2024 Satellite Events. Springer LNCS, Vol.15344, pp.254-258. Download the author manuscript Rikačovs S. and Čerāns K. Visual Data and Schema Queries over Knowledge Graphs. To appear in EKAW'2024 Satellite Proceedings, CEUR Workshop Proceedings. Download the author manuscript Čerāns K, Bojārs U, Ovčiņņikova J, Lāce L, Grasmanis M, Sproģis A. Towards Visual Federated SPARQL Queries. In: SEMANTiCS-PDWT 2024 CEUR Workshop Proceedings Vol 3759, 2024. https://ceur-ws.org/Vol-3759/paper24.pdf Lāce L, Romāne A, Grasmanis M, Čerāns K. A Method of Visual Presentation of Data Schemas. In: Visualization and Interaction for Ontologies and Linked Data 2023. Vol 3508. CEUR Workshop Proceedings. 2023:57-62. https://ceur-ws.org/Vol-3508/paper6.pdf Bojārs U, Ovčiņņikova J, Lāce L, Sproģis A, Grasmanis M, Čerāns K. Integrating Sparklis and ViziQuer for Enhanced SPARQL Querying and Visualization. In: Visualization and Interaction for Ontologies and Linked Data 2023. Vol 3508. CEUR Workshop Proceedings. 2023:41-48. https://ceur-ws.org/Vol-3508/paper4.pdf Ovčiņņikova J, Šostaks A, Čerāns K. Visual Diagrammatic Queries in ViziQuer: Overview and Implementation. Baltic Journal of Modern Computing. 2023;11(2):317-350. doi:10.22364/bjmc.2023.11.2.07 Čerans K, Ovčinnikova J, Grasmanis M, Lāce L. Experience with Visual SPARQL Queries over DBPedia. In: Visualization and Interaction for Ontologies and Linked Data 2022. Vol 3253. CEUR Workshop Proceedings. 2022:59-65. https://ceur-ws.org/Vol-3253/paper6.pdf Čerāns K, Ovčiņņikova J, Grasmanis M, Lāce L. Towards UML-Style Visual Queries over Wikidata. In: The Semantic Web: ESWC 2022 Satellite Events. Vol 13384. LNCS. Springer; 2022:11-15. doi:10.1007/978-3-031-11609-4_2 Download the author manuscript K.Cerans, L.Lace, M.Grasmanis, J.Ovcinnikova. A UML-style Visual Query Environment over DBPedia. In Proc. of MTSR'2021, Springer Verlag CCIS Series Download the author manuscript K.Cerans, J.Ovcinnikova, M.Grasmanis, L.Lace and A.Romane. Visual Presentation of SPARQL Queries in ViziQuer In Voila!2021, CEUR Workshop Proceedings, Vol.3023 Čerāns, K., Ovčiņņikova, J., Bojārs, U., Grasmanis, M., Lāce, L. and Romāne, A., Schema-Backed Visual Queries over Europeana and Other Linked Data Resources. ESWC 2021 Satellite Events. Springer LNCS, Vol.12739, pp.82-87. Download the author manuscript K.Cerans, A.Sostaks, U.Bojars, J.Ovcinnikova, L.Lace, M.Grasmanis, A.Romane, A.Sprogis and J.Barzdins. ViziQuer: a Visual Notation for RDF Data Analysis Queries. In Proc. of MTSR'2018, in Springer Verlag CCIS Series Download the author manuscript K.Cerans, A.Sostaks, U.Bojars, J.Ovcinnikova, L.Lace, M.Grasmanis, A.Romane, A.Sprogis and J.Barzdins. ViziQuer: a Web-based Tool for Visual Diagrammatic Queries over RDF Data In The Semantic Web: ESWC 2018 Satellite Events, Springer Verlag Lecture Notes in Computer Science, Vol.11155, pp.158-163. Download the author manuscript K.Cerans, J.Barzdins, A.Sostaks, J.Ovcinnikova, L.Lace, M.Grasmanis and A.Sprogis. Extended UML Class Diagram Constructs for Visual SPARQL Queries in ViziQuer/web In Voila!2017, CEUR Workshop Proceedings, Vol.1947
Earlier Research	K.Cerans, J.Ovcinnikova. ViziQuer: Notation and Tool for Data Analysis SPARQL Queries. In Voila!2016, CEUR Workshop Proceedings, Vol.1704 K.Cerans, J.Ovcinnikova, M. Zviedris. SPARQL Aggregate Queries made easy with Diagrammatic Query Language ViziQuer. In ISWC 2015 Posters & Demonstrations Track, CEUR Workshop Proceedings, Vol.1486 K.Cerans, J.Ovcinnikova, M. Zviedris. Towards Graphical Query Notation for Semantic Databases. In BIR 2015, Springer LNBIP. G. Barzdins, S.Rikacovs, M. Zviedris. Graphical Query Language as SPARQL Frontend. In Local Proceedings of 13th East-European Conference (ADBIS 2009), pp. 93-107. Riga Technical University, Riga. (2009) G.Barzdins, E.Liepins, M.Veilande, M.Zviedris, "Ontology Enabled Graphical Database Query Tool for End-Users", Selected papers from DBIS'2008, Hele-Mai Haav (Eds.), Frontiers in Artificial Intelligence and Applicatons series, IOS Press, 2009. 187:105-116