EXPERIMENTS WITH NOTARIES ABOUT THE SEMIOLOGY OF 3D CADASTRAL MODELS
Keywords: 3D symbolization and cartography, semiology, visual variables, user's requirements, 3D cadastre
Abstract. Based on the hypothesis that 3D cadastral models are helpful for notaries, this study investigates the performance of visual variables for the visualization of 3D models. The approach undertaken uses face-to-face interviews with notaries involved in co-ownership establishment. A 3D geometric model of a complex condominium building is used as the studied case to which a selection of visual variables is applied. Thirty visual solutions are tested against six notarial visualization tasks and notaries are asked several questions. Based on the preliminary responses, we can now say that colour is the visual variable most appreciated by notaries, regardless of the visualization task. The use of transparency is helpful in many cases, more specifically when reading annotation (official measures). However, confusion arises when too extensive geometry of 3D lots is viewed simultaneously, and unnecessary when the geometry of the lots is fully visible. Moving the position of the geometry of a group of lots (by floor for example) looks also promising. Although this interview-based approach is subjective and empirical, it helps us to better consider the end-user's interests and take into consideration their professional opinion and requirements. The 30 visual solutions produced during these first experiments constitute a useful foundation for further analysis.