| The rapid development of spatial information data acquisition technology has produced a large amount of data,which has brought greater pressure on the data processing process.High Performance Geo-Computation(HPGC)technology is playing an important role in spatial information processing because of its powerful computing capability at the same time.However,often the High performance computing(HPC)platforms are usually heterogeneous,geographically distributed,and there are varieties of programming models.Thus,the researchers are required to master high performance computing-related techniques when using HPC technology for spatial information technology processing.Meanwhile,with the rapid development of spatial information research and the continuous expansion of applications,the entire processing process is continuously divided into many sub-processes and become increasingly complicated.It undoubtedly increases the operation difficulty and the research cost.Therefore,how to construct a process that is based on HPGC and contains many intermediate links for automatic spatial information processing is an issue worth exploring.Web Service is a remote call technology that spans programming languages and operating system platforms.It enables users not have to pay too much attention to the internal implementation details of the service in order to use it.The workflow technology enables automatic completion of the process without external intervention in accordance with a pre-defined business process consisting of multiple sub-tasks to achieve the automation of the process.Therefore,applying Web services and workflows technologies to spatial information processing will undoubtedly make complex spatial information processing easier.To sum up,based on Web Service and Activiti5 workflow technology,this paper builds a workflow-based Web service chain processing flow to simplify the complex operations of complex spatial information processing;at the same time,it combines high performance computing techniques to improve the processing efficiency of the subprocesses,and build a Web portal to achieve specific applications.The main research content is as follows:(1)We design and implement workflow-based HPGC computing service platform proposed in this study based on Java Web and Activi5 workflow and related technologies,after analyzing the background requirements and functional requirements of the platform design.(2)A general release model for HPGC-based spatial information algorithm service is proposed to facilitate the Web services construction of spatial information processing algorithm,using the Web Service technology and the popular open source workflow engine,Apache Axis2.(3)Taking the spatial information processing application of extracting the ridgeline and valley lines of the topographic features from DEM data as an example,the entire process is divided into several sub-processes from the point view of data acquisition to data processing.The step-by-step processing process not only has the serial processing module based on ArcGIS and Python,but also has some parallel processing modules with different parallel methods on different HPC platforms.These step-by-step sub-processing modules will be released and deployed on the platform proposed in this paper,and run under the controlling with the workflow-driven manner.Compared with the application examples of DEM data processing using traditional processing method,it is found that the approach studied in this paper has the advantages of convenience,speed,accuracy and efficiency,which meets the system requirements. |
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