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The Establishment of Earthquake Emergency Command Information System Based on GIS ZENG Jun1,2, ZHANG De1,2 1. Surveying and Mapping Institute, Information Engineering University, P.R.China, 450052 2. Xi’an Research Institute of Surveying and Mapping, P.R.China, 710054 [email protected] Abstract: It is a powerful guarantee to establish a full-functioned and effective earthquake emergency command information system for the government realizing earthquake-preventing, disaster reduction, rapid response and scientific decision-making. This paper discusses an architecture which is composed of C/S and B/S of earthquake emergency command information system and details the main functions and techniques of the data service layer, application service layer, web service layer and client application layer. Based on the GIS platform, the system can integrate the disaster information, predict scheme, command and dispatch with the geographic information. It is beneficial for the governor to accurately master the disaster situation and make commands scientifically. Keywords: earthquake emergency command, disaster situation representation, rapid response 1 Introduction There are three main measures to deal with the earthquake disaster in the world. One is to strengthen the earthquake predict, the second is to enhance the quality of building and the third is to improve the efficiency of the emergency command and rescue during the time of earthquake. But viewed from the situation of earthquake-preventing and disaster reducing, it is impossible to solve the difficult problems of earthquake predict and complete the anti-earthquake project in a short time. So, in general, some measures to enhance the emergency command capacity are adopted to relieve the disaster as much as possible and stable the social order in the disaster zone. Taking GIS as the basic platform, the earthquake emergency command information system is a technical system which provides anti-earthquake and disaster relief services to the government. It owns various functions, such as earthquake information acquisition, fast assessment, predict scheme management, earthquake resource management, geographic data management, task plot, command and control, emergency collaboration, disaster situation presentation, information release, information query and so on. It is a tool for the governor and the expert to execute the disaster analysis and emergency command, and a platform for the civilians to cognize the disaster and know of the rescue progress. 2 The Construction of Emergency Command Information System Command center LAN 2.1 The architecture of system In order to not only meet the needs of data and system maintenance in LAN and implementing professional and advanced analysis, but also meet the needs of earthquake information release on Internet/ Intranet and the civilian’s disaster information query, the earthquake emergency command system adopts a combination architecture [1] which takes the C/S as the main structure and the B/S as the auxiliary. Its architecture is as Client Application server Database server Administrator Browser Browser Client Web server Internet Internet\Intranet Browser Browser Browser Figure 1 The architecture of system 164 Client Other customer Client figure 1. The C/S architecture has three layers: data service layer, application service layer and client application layer and adopts the mode of fat client and thin server. Taking the data management as an example, which includes data defining, query ,edit and update, the data management is run in database server and in the client, and the system application is implemented by client software. When the client sends data request to the database server, the server executes the query operation or other business logic. Next, it obtains the data which includes basic geographic information and earthquake thematic data from the database, then send the information and data to the client. The client completes the application function of data. The client also can extract the data subsets from the database server and store them locally to establish the local database. So the system can run separately from the database server to meet the needs of mobile user and front command post to execute tasks. The B/S architecture adopts four layers, namely, the data service layer, application service layer, web service layer and browser application layer in the client. Utilizing the B/S mode, the data query and function release are implemented by the software in the browser. In the B/S mode, the program of business department in the client is designed as universal software, but the function nodes and their interior functions are privilege- limited. By the authorization, different customer is authorized different function according his or her privilege, then he or she can not use the other functions. So it can fulfill the task responsibility and enhance the data safety. 2.2 Data service layer The earthquake emergency database is responsible for the storage of basic geographic data and different kinds of earthquake and geology thematic data and provides the necessary data for the query and dispatch of the earthquake preventing and disaster relief material, predict scheme representation, disaster analysis, command and control. 2.2.1 The architecture of database management system The emergency database manages the data Client Application by relational database management system. ArcSDE client ArcSDE client The spatial data management utilizes ESRI (Indirect) (Direct) ArcSDE. ArcSDE is a kind of data access middleware, which can safely and TCP/IP effectively access the distributed geographic ArcSDE application server database[2]. The architecture of this SQL command emergency database management system is SQL as figure 2. SQL engine 2.2.2 The construction flow of database The data managed by the system includes Storage management multi-scale basic topographic data, remote sensing image, DEM data, attribute data, multimedia data, earthquake and geology Data file thematic data and so on. These data are RDBMS stored in the Geodatabase in the form of FeatureDataset. The management, index and Server dispatch of data are executed by ArcSDE. The design process of Geodatabase includes: Figure 2 The architecture of database use view modeling, entity and relation defining, entity representation determination, matching with Geodatabase model, geographic dataset organization. The former three processes are conceptual modeling process. They are not involved in concrete modeling and don’t need to consider the type of database model. The latter two processes are the logic data modeling. Their concrete processes are as follows: First, the geographic entity is represented as Geodatabase model. Its contents include: the determination 165 of the representation type of every kind of geographic entity and topologic relationship, the definition of attribute field of every kind of entity. Secondly, the data is stored in the geodatabase. It includes classifying the features into class and subclass, determining the topologic relationship of features, establishing the geographic dataset and combining the feature dataset and data class. For the digital topographic map, the process steps from the original data to final data in database should include original data checking, layer merging, data format converting, map sheet joining in the same scale, plane topology and geometric network constructing and so on. In every process step, the data should be checked in order to control the quality and precision of data. The work flow of putting topologic map data into database is as figure 3. ArcGIS Desktop Original topographic map data toolkit Need to check the spatial attribute and coordinate before and after data conversion Map layer merge ArcCatalog Format conversion Need to note the layer s source ’ ArcCatalog Map sheet join ArcCatalog ArcCatalog Topology reconstruct The attribute data should be consistent before and after topology reconstruct Check data before and after it is put into the database in order to guarantee its consistence Put data into database Figure3 The work flow of putting topologic map data into database 2.2.3 The security mechanism of geographic database ArcSDE utilizes the security means of database to ensure the safety of geographic data. It doesn’t share data in file system. The user can’t copy and delete dataset and only can access data by data interface to guarantee the legality of data access. ArcSDE provides a series of commands to authorize data access. So it is convenient to authorization management and provides data backup mechanism to safeguard geographic data and its utility. 2.3 Application service layer and web service layer 2.3.1 Application service layer The application service layer includes basic GIS service, emergency data service, business logic service, application module service and so on. The basic GIS service provides basic information analysis service. The emergency data service mainly is geographic data service which is implemented by ArcSDE. The business logical service provides the methods that the system needs. The client completes the business 166 work by calling the methods. The application modules include a series of analytic computing module, such as earthquake disaster assessment module which provides the destroy prediction of city building and lifeline engineering, the assessment of subordinate disaster, economic loss and the civilian casualty[3]. By utilizing these modules, the client can realize more complicate analysis. 2.3.2 Web service layer The web service layer is the special layer of B/S in the system. It adopts such tools as WSDL (Web Service Definition Language), UDDI (Universal Description Discovery and Integration), SOAP (Simple Object Access Protocol) and techniques to describe, register and release any kind service provided by the application layer. This layer is transparent to the client. It separates the client layer from the application service layer. The user’s request of server is packed as SOAP package through the network and sent to web service layer. After received the package, the web service layer unpacks it and extracts the request information. Then the service layer sends the information to the application service by the special communication means of the application service layer. After the application service layer replies the user with the demanded data, the demanded data is packed as the SOAP package by the web service and returned to the user. Meanwhile, the web service can realize load balance management. When many users need to access application server at the same time, the information requests can be effectively sent to different servers[4]. 2.4 Client application layer The internet \intranet is based on B/S architecture. The client accesses the servers by TCP/IP, SOAP in the form of web page. The client is used by the public. It displays the disaster information (see figure 4) released by the command information center and also can execute such simple operations based on GIS as basic map operation(zoom, roam, query), map analysis (buffer analysis, distance and area analysis) and so on. Through these functions, the public can rapidly inquire the spatial position and attribute information related with the earthquake-preventing and disaster reduction on map. Figure 4 Disaster situation release map Figure 5 Civilian evacuation route map The LAN is based on C/S architecture. The client is divided into two kinds. One is for the business department staff to do some daily maintenance, such as the update of earthquake emergency data, network control, user’s privilege management and so on. The other is for the leader and earthquake expert. This kind of client integrates the main subsystem and function modules of emergency command for disaster assessment, emergency command and decision-making. The command control subsystem is composed by the modules such as command and control, resource management, command and communication, monitoring and display. The command and control module is responsible for the planning, information sending down, monitoring, canceling and modification of task. The resource management module is responsible for resource allotting and dispatch, monitoring and warning, resource supplement. The command and communication module is responsible for the message transfer, 167 filter control, display, message conversion and so on. The monitoring and display module is responsible for the map display, GPS positioning, BD satellite positioning, LBS, video display, situation plot display, communication monitoring and so on. Figure 5 shows the route of evacuating civilian. The main function modules are as following figure 6 in LAN. Figure 6 The main function modules of C/S client 3 Conclusion It is the importance period 24 hours after the earthquake for rescuing, preventing subordinate disaster occurring and extending. So the time and efficiency of the emergency command is very important and the responsibility of rescue can’t be neglected. It is very urgent to construct a highly effective earthquake emergency command information system. The earthquake emergency command information system provides the government technical support to rapidly cognize earthquake, acquire the rescue information and evacuate the victims. The intelligent analytic assessment models can aid decision-making, rapidly response, make emergency scheme and execute command and dispatch visually based on geographic spatial data. In addition, under the visual geographic environment, the related government can collaborate smoothly. All those characteristics can remarkably improve the comprehensive capacity of earthquake-preventing and disaster reduction. Author in brief: Zeng Jun: Senior engineer in China. Research interest is GIS applications. Email:[email protected] Zhang De was born in Hubei, China. He has got his master’s degree for map cartography and GIS engineer. Now he works in Xi’an research institute of surveying and mapping. His research interests include GIS application, terrain analysis. References [1]. Zeng Jun, et al. Emergency Information Command System for Civil Air Defence [national technical report]. Xi’an research institute of surveying and mapping, 2009:4~6(in Chinese) [2]. Xiong Lihua ,Yang Feng. Application Study of Spatial Database Technology Based on ArcSDE. Computer Engineering and Design,2004,24(3):90~92(in Chinese) [3]. Meng Xiangrui. The Study of WebGIS-based Earthquake Prevention and Disaster Mitigation Information System. Jilin University,2005:41~44(in Chinese) [4]. Zhong Xiao. The Research on the GIS Application in the Earthquake Emergency System and Earthquake Information Share. The Institute of Earthquake Predict. China Earthquake Bureau,2006:3~4(in Chinese) 168