A comparative analysis of 3-D representations of urban flood map in virtual environments for hazard communication purposes

The flood hazard/risk maps do not allow a non-expert audience an immediate perception of the flooding impacts. Therefore, we need to modernize maps providing new communication approaches. In this context, 3-D representations of flood inundation through emerging formats in virtual and augmented realities may be considered as a powerful tool to engage users with flood hazards. The challenge of the research is to create a virtual 3-D environment aimed at supporting the public, practitioners and decision-makers in interpreting and understanding the impact of simulated flood hazards. For this purpose, the paper aims to perform a comparative analysis of two techniques to carry out the 3-D realistic visualizations of a flood map for representing a potential flooding of the Crati River, in the old town of Cosenza (South of Italy). The first approach develops a simple and quick workflow that provides an overall look at a neighbourhood level, but reveals some limits in water level visualization at the individual buildings scale. The second one requires additional terrestrial laser scanning (TLS) acquisition and overcomes some limits of the first approach, by providing a visual insight about water level close to building facades.