Gianfranco Gliozzo Msc GIMA Master thesis Bridging the gap between user generated spatial content and the semantic web Bridging the gap between user generated spatial content and the semantic web Master of Science Thesis Gianfranco Gliozzo December 10 th 2010 Professor: Prof. Dr. M.J. (Menno-Jan) Kraak, Department of Geoinformation Processing Faculty of Geoinformation Science and Earth Observation University of Twente Supervisor: Dr. Ir. Rob Lemmens Department of Geoinformation Processing Faculty of Geo-Information Science and Earth Observation University of Twente Supervisor: Aldo Gangemi Senior Researcher Semantic Technology Lab (STLab) Institute for Cognitive Science and Technology, Italian National Research Council (ISTC-CNR) Reviewer: Mw. drs. M.E. (Marian) de Vries OTB Research Institute for the Built Environment Delft University of technology i Gianfranco Gliozzo Msc GIMA Master thesis Bridging the gap between user generated spatial content and the semantic web ii Gianfranco Gliozzo Msc GIMA Master thesis Bridging the gap between user generated spatial content and the semantic web Acknowledgments The present work could not have been completed without the loving support of my parents and my sister, old and new friends made on the occasion of the thesis. Let me quote my cousin, Alfio, always ready to stimulate and to suggest visions from a different perspective, he is the “guilty”, who suggested me the way of the semantic web and introduced me to Aldo Gangemi. Aldo Gangemi I will always be grateful for his generous support. The fantastic community of OpenStreetMap with in particular I want to thank simone (Simone Cortesi) for our long and pleasant conversations on OpenStreetMap story and perspectives and for his kind suggestions, tosky as well (Luigi Toscano) and David Paleino for their generous and tireless support in the struggle with open source applications and operating systems. iii Gianfranco Gliozzo Msc GIMA Master thesis Bridging the gap between user generated spatial content and the semantic web Table of contents Acknowledgments ............................................................................................................. iii Table of contents.................................................................................................................iv Table of figures..................................................................................................................vii Table of tables.................................................................................................................. viii Abstract................................................................................................................................1 PART I: TECHNOLOGIES, TOOLS AND RESOURCES............................................3 1 Chapter one: background. ..........................................................................................4 1.1 Introduction ...........................................................................................................4 1.2 Web2.0 or social web ............................................................................................4 1.3 Geoweb2.0.............................................................................................................5 1.4 Quality of Crowdsourced data...............................................................................5 1.5 VGI data quality analysis ......................................................................................6 1.6 Modelling the problem: semantic heterogeneity in multiple databases ................7 1.7 Naming conflict: solving approaches....................................................................7 1.8 Web 3.0 or semantic web.......................................................................................8 1.9 Geoweb3.0.............................................................................................................9 1.10 A step further – innovation aimed at ..............................................................10 Research aims ...............................................................................................................10 1.11 Problem setting...............................................................................................10 1.12 Problem statement ..........................................................................................12 1.13 Research objectives and questions..................................................................12 1.14 Research Limitations ......................................................................................13 Extent limitations:....................................................................................................13 1.15 Research Method ............................................................................................14 Method Extent limitations........................................................................................14 Research Depth limitations ......................................................................................14 1.16 Thesis development ........................................................................................15 2 Chapter two: The web environment: from web 2.0 to the semantic web. ...............16 Introduction...................................................................................................................16 2.1 The web of data ...................................................................................................16 2.2 Semantic web stack .............................................................................................16 2.3 Queries in SPARQL ............................................................................................19 2.3.1 Query forms ...............................................................................................19 2.3.2 Dealing with precision...............................................................................20 2.4 Ontologies ...........................................................................................................20 2.4.1 Formalised ontologies................................................................................21 2.4.2 Ontology matching.....................................................................................22 2.4.3 Elicited ontologies .....................................................................................22 2.4.4 Ontologic precision/expressivity ...............................................................23 2.4.5 Ontologies and folksonomies.....................................................................24 2.5 The environment of the proposed development: Linking Open Data.................25 2.5.1 DBpedia .....................................................................................................26 2.5.2 Geodata in DBpedia...................................................................................26 iv Gianfranco Gliozzo Msc GIMA Master thesis Bridging the gap between user generated spatial content and the semantic web 2.6 WordNet and WordNet RDF/OWL .....................................................................27 2.6.1 WordNet data model ..................................................................................28 2.6.2 Previous applications of WordNet in GI....................................................29 2.6.3 WordNet in the semantic web....................................................................29 2.7 Folksonomies and the semantic web...................................................................30 2.8 Maturity of ontology development......................................................................32 3 Chapter three: Geoweb 2.0 and OpenStreetMap......................................................33 Introduction...................................................................................................................33 3.1 OpenStreetMap and VGI.....................................................................................33 3.2 Data in OpenStreetMap.......................................................................................36 3.3 The OSM structure ..............................................................................................37 3.4 Data format..........................................................................................................38 3.5 Database ..............................................................................................................39 3.6 Tools to extract data.............................................................................................42 4 Chapter four: OpenStreetMap and the semantic web ..............................................43 Introduction...................................................................................................................43 4.1 Geographic Information ontologies.....................................................................43 4.2 Semantic efforts and OpenStreetMap..................................................................44 4.3 The Semantic MediaWiki – Machine readable map feature list effort................45 4.4 LinkedGeoData ...................................................................................................46 4.4.1 Overview....................................................................................................46 4.4.2 The LinkedGeoData ontology....................................................................46