Thematic workshop on building an ontology of generalisation for on-demand mapping

A workshop comprising experts in the field of map generalization came together with experts in ontological modelling in order to explore the role of ontologies in map generalization. A sequence of participatory activities identified the need for ontologies related to tasks, algorithms, data quality and truth, content selection, layout constraints, and geographical modelling (the set of relations among a set of map features). The workshop resulted in a deeper shared understanding of relationships between concepts that lie at the heart of map generalization. At the conclusion to the workshop attendees were tasked with developing case studies that will be shared via a wiki, and reported upon in a subsequent meeting devoted to ontological modelling for map generalization. This report is not exhaustive in its presentation of all the ideas and material presented at the workshop, but seeks to convey the over-arching methodology and its core findings. Introduction A one and a half day workshop was held in Paris in March at the offices of the IGN, the French national mapping agency. Organised by the ICA Commission on Map Generalization and Multiple Representation, the purpose of the workshop was to explore the relevance of ontologies to the map generalization process. The 15 attendees were a mix of practitioners, GIS vendors and researchers (Appendix A). The decision to host such a workshop followed from a previous workshop held in Vienna in September 2014 prior to the GIScience 2014 conference. Various ontology research activities have taken place over the past decade, notably work at IGN France and the Ordnance Survey of Great Britain (Gould et al., 2014). The workshop was seen as an effective way of pooling expertise and experiences, and further progressing collaborative efforts to develop ontologies relevant to map generalization research. Professor Robert Stevens and Dr. Sean Bechhofer (experts in methodologies for collaboratively building ontologies) led the workshop. Motivation Over the past 50 years, research has led to the design and implementation of countless algorithms for manipulating features represented in vector space. There now exists different taxonomies of operators and algorithms, and models that anticipate varying levels of human intervention and interaction. One measure of the success of this research is the high level of automation achieved in map generalization for specific map types and scale ranges. Some argue that insufficient emphasis has been given to understanding how the underlying geography affects the choice and application of generalization algorithms. Others have expressed a desire to share various software solutions, whilst others have observed the inconsistencies that exist in definitions of operators and evaluation criteria. There is also a desire to link the user (and their task) more closely with map generalization processes, in anticipation of web based services able to support visualisation of user generated content or other kinds of thematic data, more and more available with the web 2.0 and the open data movement, this data being itself integrated with other data. Can ontologies help us with any of these tasks? Ontologies are not a magic bullet to solving all map generalization research problems but if they can bring a shared clarity as to the underlying concepts, then this will greatly facilitate the sharing (and integration) of research outputs, such as generalisation algorithms. 1 http://generalisation.icaci. org/