Evaluation of a Volunteered Geographical Information Trust Measure in the case of OpenStreetMap

iii ACKNOWLEDGEMENTS I would like to offer my thanks to my supervisor Dr Carsten Keßler and my co-supervisors Prof Dr Jorge Mateu and Prof Dr Pedro Cabral for their willingness to supervise me. Their interest, support and guidance were of great importance for the progress of this work. At times of despair, their positive attitude helped me to pick up the pace and regain confidence. I would like to thank my parents Jan and Désirée de Groot, whose door is always open, who are always supportive and whose ears are open for all types of news, good or bad. I would also like to thank the Schenke family in Münster-Hiltrup for trusting me as a good tenant and being very nice and helpful neighbours. Thanks to them an accommodation problem at the start of the thesis semester was solved. Thanks as well to my all my friends and class mates. Meeting with them every now and then brought the joy that recharged and stimulated me to stay tuned and make the best of life and work. I would like to thank the European Commission and the organisers of the Erasmus Mundus Master Programme Geospatial Technologies for selecting me and making it possible for me to study and gain skills and knowledge in the field of GI Science. Also the experiences of living in Portugal and Germany and especially studying with, working together with, and making new friends with people from all over the world are for me of great value and I am very thankful for that as well. ABSTRACT The presence of Volunteered Geographical Information is attracting research because its high availability and diversity make it an interesting source of information. For many organisations it is important that quality of geographical information is of a certain level. Recent developments in studies related to VGI direct towards the estimation of its quality through the notion of trust as a proxy. For this thesis is investigated which factors have an important influence on trust and a simple approach was used to come up with an indication of trust levels for geographical features. The indicators were selected based on a literature review and on a dataset extracted from the open mapping project OpenStreetMap. Numbers of users, versions and confirmations were counted or calculated and involved as positive indicators, while numbers of various corrections were treated as indicators having a negative influence on …