Web-based flood monitoring system using Google Earth and 3D GIS

The flood monitoring system has become important in Japan because of global warming. Geographic Information Systems (GIS) related to Google Earth have become effective tools for analyzing flood disasters, especially for three-dimensional (3D) analysis. 2m Digital Surface Model (DSM) is the most important data for the present flood monitoring system, and was used for generating precise contour lines in the present system. It is quite effective for various applications with GIS, having enough resolution to distinguish individual houses and to analyze the flow direction of water. A Key-hole Markup Language (KML) file for Google Earth is created by ArcGIS or Google SketchUP from GIS data. One output result of the present monitoring system is inundation zone maps, which are estimated from 2m DSM depending on rainfall rates and accumulations. The flow analysis is accomplished using hydrologic tools in the Spatial Analyst Extension of ArcGIS.