This paper discusses the use of spatial data for risk and natural disaster management. The importance of remote-sensing (RS), Geographic Information System (GIS) and Global Navigation Satellite System (GNSS) data is stressed by comparing studies of the use of these technologies for natural disaster management. Spatial data sharing is discussed in the context of the establishment of Spatial Data Infrastructures (SDIs) for natural disasters. Some examples of SDI application in disaster management are analyzed, and the need for participation from organizations and governments to facilitate the exchange of information and to improve preventive and emergency plans is reinforced. Additionally, the potential involvement of citizens in the risk and disaster management process by providing voluntary data collected from volunteered geographic information (VGI) applications is explored. A model relating all of the spatial data-sharing aspects discussed in the article was suggested to elucidate the importance of the issues raised.

The trend of using volunteered and collaborative data in the context of natural disasters has been increasing. This fact, together with floods and inundations, which occur in the city of Sao Paulo, makes it possible to explore the volunteered and collaborative way of generating and transmitting geographic data dynamically. This can be done by using technologies affordable to the population, such as the Internet, the global positioning system and other monitoring systems embedded in mobiles. This article aims to present the proposal of a conceptual scheme for a dynamic and collaborative mapping system of flooding points, whose data source comes from people equipped with mobile devices that allow identify their locations. The results correspond to the conceptual scheme of the system as well as the prototype ‘Flooding Points’ – a map available on the web showing the flooding points in the city, which were provided at the time of the event by ordinary people. The prototype was developed by using the free and open source Crowdmap/Ushahidi platform. The system was assessed by a questionnaire answered by the users, who gave their opinion about its feasibility, as well as the adjustments which must be made for the population's effective use. It was found that the application of system for subjects of inundation and flooding is complex in relation for other types of events due to its temporal dynamics characteristics. The results of the questionnaire, applied to evaluate the system, demonstrated the public utility of the application and the interest of the population for a dynamic system that enables the exchange of information on the problem of inundation and flooding in near real time in the city of Sao Paulo.

RESUMOA tendência de utilização de dados voluntários e colaborativos em contextos de desastres naturais é crescente. Esse fato aliado aos cenários de alagamentos que ocorrem na cidade de São Paulo traz a possibilidade de exploração sobre o modo voluntário e colaborativo de geração e transmissão da informação geográfica de forma dinâmica. E estas são proporcionadas por tecnologias acessíveis à população, como o GPS (Global Positioning System) embarcado em celulares e a internet. O presente artigo tem como objetivo a proposta de um esquema conceitual para um sistema dinâmico e colaborativo de mapeamento dos pontos alagados, cuja fonte dos dados advém das pessoas equipadas com aparelhos celulares que permitem a sua localização. Os resultados apresentados correspondem aos esquemas conceituais do sistema, bem como ao protótipo "Pontos de Alagamento" -mapa disponibilizado via web com os pontos de alagamento da cidade, fornecidos no momento da ocorrência do evento por pessoas comuns. O protótipo foi desenvolvido por meio da plataforma livre e de código aberto -Crowdmap/Ushahidi. O sistema foi avaliado através de um questionário respondido por usuários, os quais opinaram sobre a viabilidade do mesmo, bem como os ajustes que devem ser realizados para o uso efetivo da população.