Open Community Data & Official Public Data in flood risk management: a comparison based on InaSAFE

Flood and – in general – natural hazards cannot be prevented; however, measures can be taken to mitigate their impacts and prevent them from becoming disasters. Disaster management has been defined as «(the)continuous process that aims at avoiding or reducing the impact of natural hazards» (Poser, Dransch, 2010). Poser and Dransch (2010) have also outlined the importance of using up-to-date and accurate information in a ll phases of disaster management, as the need of integrating information from many different sources including in-situ sensors, aerial and satellite images, administrative, statistics and socioeconomic census data. New Internet technologies have facilitated fast and easy data collection from the public, giving rise to the idea of using Volunteered Geographic Information (VGI) in disaster risk management. The paper discusses the opportunities and challenges of using VGI for disaster management, with particular focus on information for the prevention phase. This case study is based on flood risk assessment in two recently flooded cities in Veneto, Italy. We used InaSAFE, a free hazard and risk modeling application integrated in QGIS as a plug-in. InaSAFE offers the capacity to compare hazard and exposure official data with community crowdsourced data. In the case study we compare the results obtained by InaSAFE when using as input the data describing buildings (as exposure layer) drew from OpenStreetMap and from official public data. The goal of this work is answering the following question: Can OSM be used to collect exposure data for DRM? The paper ends analyzing different data sources opportunities and limits.