The GI2000 initiative considered the requirements for a geographic information infrastructure in Europe. This was followed by the European Territorial Management Information Infrastructure project, ETeMII, which among others examined the issue of reference data. Reference data sets provide a spatial context and structure for everyone involved with geographic information. An analysis of the information provided through these efforts point to the relative importance of geographic information on real property and other socioeconomic issues. - The research activity Modelling Real Property Transactions