Last modified: 2016-05-10
Abstract
Taiwan, with special geological feature, is located at the area where is easily attacked by earthquakes, typhoons and torrential rains. To protect people’s life and property, it is necessary to positively integrate all kinds of remote sensing data and geospatial information, as well as efficiently use them upon disaster prevention and mitigation. This paper presents a web-based geospatial information system (Web-GIS) that is dedicated to landslide disaster prevention and mitigation. We develop a module of superoverlay processing that is able to digest both raster and vector data and generate tiles at different levels of detail. Processed by this new module, all geospatial information related to disaster prevention, warning, response and management are compiled and integrated in the system. To enable a free and rapid access to such a huge amount of data, we select the Google Maps API as the main engine of Web-GIS. This open-source, cross-platform, free and powerful engine comes with all functions and data that are supported by Google Map. Based on Google Maps API, we also develop several friendly and flexible functions to enable the users to search, preview, overlay, compare, mark and share the big data.
In normal times, this Web-GIS serves as a warehouse/database that stores all GIS data related to landslide disaster prevention and mitigation. Based on a long-term and detailed landslide inventory derived from 12 annual composites of high-spatial-resolution (2m) satellite imagery for the entire Taiwan region, we have made several efforts to develop a nowcast system of landslide hazards. Such efforts include establishing a model for a landslide susceptibility index (LSI), introducing landslide total flux as a new preparatory factor for the model, and optimizing the weight of each preparatory factor.
During the warning of a typhoon or a storm, the landslide hazard index (LHI) is calculated from LSI and the precipitation nowcast of the Ensemble-based Typhoon Quantitative Precipitation Forecast System. The updated LHI is displayed on the Web-GIS and the hot spots of landslide are identified for intensified monitoring, in case of necessary. Whenever a landslide disaster is occurred, we will employ multi-stage remote sensing platforms, including satellite and unmanned aerial vehicle, to acquire the crucial images of disaster areas. These images will be compared to the pre-disaster images to evaluate the damages caused by this event.
Ever since this Web-GIS was established in 2011, a total of 26 landslide disaster events were occurred in Taiwan. Debris Flow Disaster Prevention Center, Soil and Water Conservation Bureau of Taiwan has been employing this system to respond to these events. Through integrating and applying all GIS data related to landslide disaster prevention and mitigation, this system enhances the ability of disaster analysis and interpretation on the issue of landslide disaster prevention and mitigation.