Research on WebGIS major hazard source system of t

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Research on major hazard source system in petrochemical enterprises (WebGIS)

the establishment of a major hazard source management system based on wegis technology will facilitate the safety management of petrochemical enterprises and is of great significance to prevent and control major hazards. This paper analyzes the characteristics of WebGIS, and introduces in detail the objectives, tasks, architecture and database design of the system, as well as the main functions and key technologies of the system

with the rapid development of computer, Internet and broadband communication technology, the traditional GIS security management system based on client/server structure has objectively become increasingly unable to meet the needs of increasingly severe security management due to the constraints of time, place and other factors. The application mode of browser/server three-level architecture based on Internet just makes up for the defects of traditional GIS, so it has increasingly become the mainstream of technological development, and has rich and unlimited potential development space. Internet has become a new GIS system platform. Using Internet technology to publish spatial data on the web for users to browse and use is the inevitable trend of GIS development. WebGIS is the product of the application of Internet and WWW technology to GIS development. Internet users can browse the spatial data in WebGIS sites from any node, make thematic maps, and carry out various spatial retrieval and spatial analysis

webgis not only has the functions of traditional GIS, but also has the unique functions of Internet

1 WebGIS is an integrated global client/server network system

webgis is to apply the concept of global client/server to perform GIS operations. Users can request data, analysis tools or modules from the server at the client. The server executes the user's request and sends the execution results back to the client through the Internet

2 WebGIS is an interactive system

webgis enables users to zoom, drag, query and label GIS maps, relevant spatial data and attribute data on the client side through the Internet, and even complete spatial query or analysis with a web browser

3 WebGIS is a distributed system

gis data and applications are independent components and modules. WebGIS uses the Internet-based distributed system to separate GIS data and applications on different computers, and each part interacts with each other through application driven intermediate components. Users can access these data and applications from anywhere in the network, that is, users can access remote GIS data and applications through the Internet without installing GIS software on their own terminals

4 WebGIS is a cross platform system

webgsi is suitable for different software and hardware platforms. As long as you can access the Internet, users can access WebGIS data through a web browser, so as to realize remote heterogeneous data sharing

the major hazard source management system of petrochemical enterprises based on WebGIS aims to establish a visual and open major hazard source network database management system combined with the characteristics of GIS and Internet, which is convenient for petrochemical enterprises to centrally manage the existing major hazard source information and its geographical environment spatial information data

1 the goal of system construction

(1) build a database of basic information of major hazard sources and related geographic information of petrochemical enterprises

(2) develop applications that can provide users with the functions of browsing, querying and analyzing the basic information of major hazard sources, the location of major hazard sources and the geographical information of their surrounding environment

(3) develop applications that enable users to prepare emergency rescue plans for major accidents and provide users with emergency plans in case of emergencies

2 tasks of the system

(1) manage the information of major hazard installations and the geographic information they are located in, and provide users with the query and analysis of relevant information

(2) provide users with emergency rescue plans for major accidents in an emergency, and assist users in making decisions

1 platform selection of the system

this system uses arcims3 of Ersi company as the development platform, and uses ASP to develop applications. Arcims3 is a new generation product of horizontal host structure based on mapping and distributed GIS, which was launched by RI with the formal consent of the major shareholders and the formal resolution of the board of directors on March 13, 2017. ArcIMS allows users to provide GIS applications and map data for browser clients in the Internet environment. The WebGIS platform is mainly selected in consideration of data compatibility and system scalability. ArcIMS supports the customized 700000 ton/year coal to olefin new material demonstration project of Shenhua Ningmei Saudi Basic Industry Company, which is located in zone a of coal chemical industry base of Ningxia Ningdong energy and chemical industry base. The client has javaviewer and HTMLViewer, which provides users with a good secondary development environment. ArcIMS runs in a distributed environment and consists of client-side and server-side components. On the server side, ArcIMS provides two ways to publish spatial data: grid data and vector data. Considering the speed of the network and other constraints, the server uses grid data to publish spatial data. Using ArcIMS to design WebGIS server can provide application services for multiple clients through the Internet; ArcIMS can also expand the server at any time to meet the growing service requests

2 system architecture design

this system adopts a client/server (b/s) three-tier architecture, which is composed of presentation layer (client), application logic layer (application server) and data layer (database server). The user requests the server to perform some operation through the client; The application server mainly responds to various requests of users and converts these requests into database requests; The database server accepts the requests of the application server, which are mainly divided into the following six categories: pressure-sensitive adhesive (tape), polymer lotion adhesive, rubber adhesive, polyurethane adhesive, hot-melt adhesive and engineering adhesive. Execute these requests and return the results to the application server; Finally, it is transformed by the application server and returned to the client. This structure separates data and data processing, and improves the stability of the system; In addition, because the client needs to execute less application code, the running speed of the client system is greatly improved. The overall structure of the system is shown in Figure 1

Figure 1 three-tier architecture of the system

the development platform and application platform adopted by the system are: (1) relational database SQL Server2000; (2) The server operating system is Microsoft 2000 server; (3) Web server adopts IIS 5.0; (4) The client operating system is windows series; (5) The client can use IE browser; (6) The GIS platform adopts ArcGIS8; (7) WebGIS adopts arcims3

3 design of database

the background database of the system includes two parts: spatial information database and non spatial information database. The spatial database is mainly used to store and manage the geospatial information and attribute information of the location of major hazard sources, divide and organize the spatial information according to the plant area where major hazard sources are located in the enterprise, and store the relevant spatial data in coverage format. Non spatial information mainly refers to the basic information of major hazard sources and emergency rescue plan for major accidents in petrochemical enterprises. Considering safety, sqlserver2000 is adopted as the database. First, major hazard installations shall be classified according to the following principles: from the perspective of operability, major hazard installations shall be classified according to the places or equipment and facilities where major hazard installations are located; Then, according to the principle of similarity and compatibility, it is carried out hierarchically according to the respective characteristics of major hazard sources. According to the above principles, major hazard sources are divided into seven categories: storage tank areas, reservoir areas, production sites, enterprise dangerous buildings, pressure pipelines, boilers and pressure vessels. Finally, take the basic information of major hazard installations (such as name, area, number, stored or transported substances and their categories) as attributes to prepare data sheets; In addition, prepare the emergency plan data table: at the same time, establish the association between the non spatial information database table and the spatial information database data table

system information retrieval and query mainly includes the retrieval of geospatial information where major hazard installations are located and the query of basic information of major hazard installations. Users can easily roam and zoom the map of the enterprise factory at will on the client; At the same time, the detailed information of major hazard installations can be directly queried on the map. The analysis of information mainly uses GIS to realize the function of auxiliary decision-making. When a dangerous situation or accident occurs in a major hazard source, users can directly find the location of the accident on the map, predict the scope of the danger or accident, call out the corresponding major accident emergency rescue plan, and select the appropriate plan to deal with the accident

2 information entry and update

information entry and update mainly includes the entry and update of basic information of major hazard installations, the entry and update of spatial information, and the preparation and adjustment of emergency rescue plans for major accidents. The input and update of the basic information of major hazard installations are mainly performed by the server-side ASP (VBScript) application program. The main work of spatial information input is the integration of multiple data sources, that is, the process of transmitting the original data (spatial data and attribute data) from various external sources and forms to the system, and transforming these data from external format into data files in a format acceptable to the system. Arc GIS supports a variety of spatial data formats, such as shape, coverage, DWG and other format files. The preparation of the emergency rescue plan for major accidents in this system is to save the plan in word as a doc format file, and then convert the file into binary and save it to the database

3 spatial information visualization function

the system provides users with intuitive functions such as zooming, panning, hierarchical display, thematic map making, etc. Visualization also includes the graphical visualization of the attribute information of spatially distributed features, that is to say, GIS realizes the integrated management of spatial information and attribute information, and can establish a relatively perfect relationship between them

the establishment of this system makes a beneficial attempt for petrochemical enterprises to apply WebGIS to manage major hazard sources, and provides valuable experience for the future promotion of WebGIS in other management fields of petrochemical enterprises. The deficiency is that the system lacks the function of quickly evaluating major hazard sources. The future work is to further improve the function of the system in rapid evaluation. With the deepening and development of enterprise Internet applications, WebGIS applications based on Internet will be more and more widely, which is undoubtedly the future development direction

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