Part 2: Information Systems, Information Modelling and SemanticsInternational audienceInformation about localized phenomena may be represented in multiple ways. GIS systems may be used to record the spatial extent of the phenomena. Observations about the state of one or more properties of the phenomena are available from real-time sensors, models, or from archives. The relationships between these data sources, or specific features in different data products, cannot easily be specified. Additionally, features change over time, their representations use different spatial scales and different aspects of them are of concern to different stakeholders. This greatly increases the number of potential relationships between features. Thus, for a give...