Research On The Function Expansion And Upgrade Of Gis-based Earthquake Prevention And Disaster Reduction System

Earthquake is a very fearful natural disaster that occurs suddenly and endangers people's life and property. It is imperative for disaster relief agencies and civil protection bodies to evaluate the damage as soon as possible after the event for emergency response. The development of Geographic Information System technology provides a good measure to cope with this disaster mitigation demand. In China, dozens of cities and large enterprises spent a lot of manpower and material resources on building their own Earthquake Prevention and Disaster Reduction System (EPDRS) based on GIS since the beginning of 1990's. Do these systems are useful or not, and how to improve the validity of those systems are discussed in knowledge and software aspects.Wenchuan Earthquake occurred on May 12, 2008 in Sichuan Province of China, which is a validation of our country's disaster mitigation work. Considering this real earthquake lesson, this paper analyzed the functional limits of EPDRS and the imperative work to improve the capability to face the sudden earthquake damage. Those works included in this paper are as follows: add new information sources and the corresponding new processing modules to assist in modifying the experiential isoseismal calculated by EPDRS; build image index of CBERS satellite on basis of the demand of disaster mitigation; detect the mountain disasters from CBERS satellite image partially overlaid by the clouds and their shadows.This paper took several real earthquake experiences as validation cases of EPDRS. The validations with thorough analysis illumined that the precision of isoseismals generated by EPDRS or any other system must be improved for a better estimation of earthquake damage; that need to absorb the new information sources.The information included in Remote Sensing and Internet is distributing in a large space scope and that can be almost updated in real time at a certain time limit; especially, being"information highway", Internet is a cheap information source, collecting information from Internet cost less workload and time consuming, it can be used to assist disaster mitigation. This paper took 5.12 Wenchuan earthquake as example to build a series methods that include: collect the describing information from Internet, get"information intensity"from the collection, interpolate in spatial range to build the prediction surface and get the contours which represent isoseismals. Human-computer interaction method was developed in this paper by move, enlarge the experiential isoseismals to deal with the deviation of the macro- from micro-epicenter, the meizoseismal area from the calculated zone by EPDRS, by which the 1st modification of the experiential isoseismals is completed; and then considering the distribution of the"information intensity"and"information isoseismals", the 2nd modification can be made. Besides setting different time nodes of information collections, the building damage assessment results of remote sensing image published in the government Webpage was considered to be converted to RS-intensity to be used to modify the isoseismals. By comparing with the ground survey result, the precision of the modification isoseismals is better more and more along with the time changing and the information amount increasing. On the 12th day after earthquake the modification of isoseismals is already similar with that from the survey report.In the aspect of RS image processing, this paper considered to realize the automation of choosing image process before downloading. RS images are big files, one scene of CBERS-CCD multi-spectrum image can be more than 100 Mb. The searching methods on the CBERS webpage are limit, and the searching results still need more time to choose the image to study. This paper took the choosing process of CBERS image as example, and broke through the conventional searching methods in, and then built the index module of choosing CBERS images by considering the demand of disaster mitigation.Firstly, ordered a certain time and space range in the CBERS Webpage to search image,built a scene-center database from the information of the search results, such as PATH, ROW, longitude, latitude etc., from which the standard scene-center point's matrix was calculated according to the satellite imaging character. Take the standard scene-center point's matrix as normal points; pick up the scene-center points in a luminal distance. Secondly, in order to obtain the better result of change detection, two choosing rules about imaging time were founded and actualized by Matlab. In the end, the chosen points were overlaid with the isoseismals, the spatial analysis method"identity"is applied to get the priority download list of CBERS images.According to the download list, pick up several images pair (pre- and post-earthquake) to detect mountain disaster. The influence of the clouds and their shadows in the RS images on the change detection of mountain disaster. Three classification methods is carried out to get the distribution of the clouds and their shadows in this paper, the precision of classification is calculated. By comparison, the decision tree built in this paper is simple to apply and had a good precision of classification. Merge the regions of clouds and their shadows in pre- and post- image to get the shielding zone, the else region is ground object zone; the damage located in the shielding zone is false damage, that in the ground object zone is the real damage.Finally, all progresses in this dissertation are summarized; the assumptions and prospects for further study are mentioned.