A Distributed Web Map Service Based On Ice

In recent years, with the rapid development of the geographic information industry, the demand for the collaboration between Web Geographic Information System(Web GIS) is growing. Due to the differences in data storage and exchange standard between GIS platforms, web map service which meet OWS is becoming the main way of collaboration between the Web GIS.Based on Ice distributed computing middleware framework, this paper has designed and implemented an efficient distributed web map service system to share map data and achieve interoperability among multi Web GIS, which improves the linkage and collaboration between multi Web GIS. According to SOA, based on the analysis of Ice Grid service, this paper has designed the overall architecture of this distributed web map service system: service presentation layer, web service layer, application service layer and management subsystem, and web service layer and application service layer have been implemented. The innovations and main content of this paper are as follows:1. On the basis of in-depth study on OWS, this paper has designed and implemented a combined with access control and cache management web service layer, which has been deployed on Nginx server and Tomcat server cluster. For OWS service requests accessed to this layer, the paper has used Nginx request filter capabilities to achieve the separation of static and dynamic content, and uses fair manner as the load balancing policy to forward dynamic content requests to Tomcat cluster. In Tomcat cluster, this paper has used Servlet to process requests for dynamic content, which was also used to transform complex computing tasks to application service requests.2. Based on the works of Ice middleware, this paper has designed and implemented an application component communication bus which connects the web service layer and the application service layer, based on the bus, this paper has transformed application service requests to remote procedure call relations. Meanwhile, according to OWS requirements, this paper has designed and implemented a communication bus interface, and which establishes the mapping relationship between OWS services and Ice services.3. On the basis of in-depth analysis of request-response relationship which is owned application service requests, this paper has putted forward an application service model based on task of private sessions. and combined with Ice Grid services and above model, this paper has designed and implemented an application service layer with Ice WFS, WMS, WMTS and WCS application service components which is deployed on the application server cluster. In this layer, for the local data and hot data in Web GIS, this paper has presented the secondary load balance policy which is that computing in advance and caching peripheral data based on the load of application server cluster.4. Through in-depth analysis of the Ice Grid Admin, Ice Patch2, Ice Storm and Ice Grid services, this paper has designed the overall architecture of management subsystem and the process of deploying and releasing a web map service.Based on the design and implementation of above system, in this paper the system has been tested with OWS service functions tests and cluster concurrent tests in the laboratory environment, and statistical analysis and test results in single and clustered environment show the scalability and high concurrency of distribution web map service system based on Ice.