ABSTRACT
It is important to build a flood-forecasting system for early warning to evacuate residents in time. Although it is straightforward to indicate the predicted inundated regions through drawing red circles on a map embedded in a Web page, such approach has some drawbacks. In this paper, we propose an alternative way by summarizing those regions to be warned according to landmarks. The corresponding output can be used to produce short text messages for easy broadcast. It can be also used for visual display in a more efficient way. We have designed and implemented two corresponding approaches to produce such output. They are the Voronoi cell approach and the threshold approach, which differ in determining the landmarks that will be influenced by the predicted inundated regions. Experimental results show that the threshold approach requires more index sizes than the Voronoi cell approach does, but it will take less execution time.
