Optimization Research And Realization Of Web GIS Services In Road Emergency Response System

With the continuous deepening of information technology,the information system for road emergency operation and monitoring has been built gradually,but there is a lack of information sources and the data is not perfect as well,therefore the system cannot directly and comprehensively display traffic information and thus cannot respond quickly to emergencies and ensure real-time monitoring of daily traffic.Applying Web GIS services to road emergency can effectively resolve the problems mentioned above.But in practice,as being affected by factors of network bandwidth,server load,etc.,the performance of Web GIS services becomes the bottleneck in the overall performance of the information system,thereby affecting the user experience.How to reduce the response time of the geographic data so as to enhance the performance of Web GIS services becomes the core issue of the application of Web GIS services in the field of road emergency response.This thesis,with the project "Ordinary Road Network Operation Monitoring and Emergency Response System" as the background,researches on the implementation of Web GIS services,focusing on the performance optimization of Web GIS services.The main work of the thesis includes the following aspects:(1)The research status and development trend of domestic and foreign Web GIS performance optimization is studied and analyzed,the impacts of different development modes and deployment model on Web GIS service performance are compared,a Web GIS framework suitable for the Road Emergency Response System is established based on analysis of the development advantage of Server API and ArcGIS Server.(2)The impacts of JS,CSS,pictures and other files on the performance of Web GIS service are studied,and the optimization strategies of compression,merging and setting up the browser cache are adopted to improve the performance of the Web GIS services.(3)The impacts of different data sources,cached map services,server deployment,slice cache storage etc.on the performance of Web GIS service are studied,and the optimization strategies of deploying ArcSDE to manage the spatial data storage,adding fusion cache to the map,deploying the virtual machine cluster on the map service and utilizing virtual memory disk to store slices are proposed,thus improving the performance of Web GIS services.(4)Based on the performance optimization strategies mentioned above,the overall design of Web GIS services for highway emergency services system for Road Emergency Response System is conducted,along with the performance optimization design and implementation and the functional design and implementation as well.And a test environment is set up to verify the feasibility and economy of the optimization strategy and the advancement of Web GIS services in Road Emergency Response System.In conclusion,the performance optimization strategies of Web GIS services are researched in this thesis,the front-end static files are compressed and merged,GIS service is deployed to a virtual machine cluster and RAM Disk is utilized to optimize memory utilization to improve the performance of Web GIS services.Also it has been applied to the Road Emergency Response System in Wuhan,Xiangyang,Shiyan,Enshi,Huangshi,Xiaogan and Suizhou City and has achieved good performance.