Citizens as Sensors for Crisis Events: Sensor Web Enablement for Volunteered Geographic Information

A set of developments within the field of geosensors is to engage citizens to act as sensors, thus providing so-called Volunteered Geographic Information (VGI). There is a long tradition of non specialists contributing to the collection of geo-referenced information. Furthermore thanks to recent convergence of greater access to broadband connections, the availability of Global Positioning Systems at affordable prices, and more participative forms of interaction on the Web (Web 2.0) vast numbers of individuals are able to create and share geographic information. The potential of up to 6 billion human sensors to monitor the state of the environment, validate global models with local knowledge, contribute to crisis situations awareness and provide information that only humans can capture (e.g. emotions and perceptions like fear of crime) is vast and has yet to be fully exploited. However, integrating VGI into Spatial Data Infrastructures (SDI) is a major challenge, as it is often regarded as insufficiently structured, documented or validated according to scientific standards. Early instances of SDIs used to have limited ability to manage and process geosensor-based data (beyond remotely sensed imagery snapshots), which tend to arrive in continuous streams of real-time information. The current works on standards for Sensor Web Enablement (SWE) aim to fill this gap. This paper shows how such SWE standards can be applied to VGI, thus converting it in a timely, cost-effective and valuable source of information for SDIs. By doing so, we extend previous works describing a workflow for VGI integration into SDI and further advance an initial set of VGI Sensing and event detection techniques. In particular, an example of how such VGI Sensing techniques can support crisis information system is provided.