Data models, Query Languages, Implemented Systems and Applications of Linked Geospatial Data

In this tutorial we survey the state of the art in data models, query languages, implemented systems and applications of linked geospatial data. Many kinds of geospatial data are becoming available as linked datasets given the proliferation of geospatial information on the Web (e.g., Google and Bing maps, user-generated geospatial content etc.). The topic of the tutorial is related to all core research areas of the Semantic Web (e.g., semantic information extraction, data modeling and ontologies, querying, reasoning, implemented systems etc.) since there is often a need to re-consider existing core techniques when we deal with geospatial information. Thus, it is timely to train Semantic Web researchers, especially the ones that are in the early stages of their careers, on the state of the art of this area and invite them to contribute to it.

Tutorial description

We have recently witnessed a proliferation of geospatial data on the Web. In addition to professionally-produced material being offered for free (e.g., Google or Bing maps), the public has also been encouraged to make geospatial content, including their geographical location, available online. The volume of such geospatial Web content is already big and constantly growing.

Semantic Web researchers and practitioners have also started to make geospatial data available as linked data (e.g., Ordnance Survey, Great Britain's national mapping agency, makes available some of its geospatial data as linked data (http://data.ordnancesurvey.co.uk/.html), the portal LinkedGeoData makes OpenStreetMap data are made available as RDF (http://linkedgeodata.org/ etc.). Since a lot of data useful to the wider public is geospatial (e.g., open government data), we expect this trend to continue in the near future.

In this tutorial we will present the state of the art in data models, query languages and implemented systems for linked geospatial data i.e., geospatial data expressed in RDF.

Intended audience - Prerequisite knowledge

The tutorial is targeted towards Semantic Web researchers in the early stages of their career. The prerequisite is good knowledge of RDF and SPARQL and some knowledge of other Semantic Web technologies (OWL, RDF stores, linked data). Knowledge of geospatial technologies is not a prerequisite and will be covered in some depth.

Detailed description

14:00-14:15 Introduction [Presentation: ppt | pdf]

14:15-15:00 Background in geospatial data modeling [Presentation: ppt | pdf]

  • GIS concepts and vocabulary
  • Geographic space modeling and representation (vector space representation, half-space representation)
  • Co-ordinate systems
  • Relevant OGC standards (Well Known Text, Geography Markup Language)

15:00-15:30 Geospatial data in the Semantic Web - stSPARQL [Presentation: ppt | pdf]

  • Representing geospatial data in stRDF
  • Examples of publicly available linked geospatial data
  • Querying geospatial data using stSPARQL

15:30-16:00 Coffee Break

16:00-16:30 Geospatial data in the Semantic Web - GeoSPARQL [Presentation: ppt | pdf]

  • The query language GeoSPARQL.

16:30-16:45 Implemented systems  [Presentation: ppt | pdf]

  • Survey of implementations of stSPARQL, GeoSPARQL and other research prototypes
  • Survey of geospatial features in well-known RDF stores

16:50-17:00 Applications [Presentation: ppt | pdf]

  • Survey of existing applications of linked geospatial data. Emphasis on an application the presenters have developed on Earth Observation data.  
17:00 - 17:15 Conclusions, questions, discussion [Presentation: ppt | pdf]
17:15 - 17:30 Demo of Strabon [link]

Presenter CVs

Manolis Koubarakis is a Professor in the Dept. of Informatics and Telecommunications, National and Kapodistrian University of Athens. He has a degree in Mathematics from the University of Crete, an M.Sc. in Computer Science from the University of Toronto, and a Ph.D. in Computer Science from the National Technical University of Athens. He joined his current department in September 2005 as an Associate Professor and was promoted to Professor in April 2011. Before coming to Athens, he has been an Assistant and Associate Professor in the Dept. of Electronic and Computer Engineering, Technical University of Crete, and a Lecturer in the Dept. of Computation, University of Manchester – Institute of Science and Technology (UMIST). Manolis has published more than 100 papers that have been widely cited in the areas of Artificial Intelligence (especially Knowledge Representation), Databases, Semantic Web and P2P Computing. His research has been financially supported by the European Commission (projects CHOROCHRONOS, DIET, BRIDGEMAP, Evergrow, OntoGrid, SemsorGrid4Env and TELEIOS), the Greek General Secretariat for Research and Technology and industry sources (Microsoft Research and British Telecommunications). He is currently co-ordinating project TELEIOS (http://www.earthobservatory.eu/) which is building an Earth Observatory using a combination of technologies based on semantics (geospatial extensions of RDF and SPARQL) and array extensions of SQL. Manolis has 16 years teaching experience in academic institutions in Greece and the United Kingdom, and has given many talks in international conferences and workshops (some of them invited). He has served as Tutorial chair for ESWC 2011.

Kostis Kyzirakos is a researcher in the Department of Informatics and Telecommunications, University of Athens. He received his Diploma in Engineering from the School of Electrical and Computer Engineering, NTUA, Athens. He has participated in projects funded by the European Commision (Ontogrid, SemsorGrid4Env, TELEIOS) and the Greek General Secretariat for Research and Technology (P2P Techniques for Semantic Web Services). He is one of the main developers of the semantic geospatial DBMS Strabon that was developed in the context of the EU projects SemsorGrid4Env and TELEIOS. In the same context, he studied and proposed how to represent and query geospatial data in the Semantic Web, published various geospatial datasets as linked geospatial data and implemented applications combining these data with previously published linked geospatial data. His current research focuses on modeling and querying semantic spatio-temporal information on top of traditional DBMS. He has given a tutorial on building semantic sensor webs and applications at ESWC 2011.

Manos Karpathiotakis is a researcher in the Department of Informatics and Telecommunications, University of Athens. He received his Bachelor degree and his Master of Science from the Department of Informatics and Telecommunications of the University of Athens. He has participated in projects funded by the European Commision (TELEIOS, SemsorGrid4Env) and he is one of the main developers of the semantic geospatial DBMS Strabon that was developed in the context of these projects. In the same context, he published various geospatial datasets as linked geospatial data and implemented applications combining these data with previously published linked geospatial data. His current research focuses on the overlapping areas of Geospatial Semantic Web, Semantic Sensor Web and Linked Data.