Metafunction-oriented GIS Analysis and Design

In the view of software engineering, this article describes several traditional analysis and design methods of information system.Considering the characteristic of development of GIS technology, this article presents a method for GIS analysis and design, which is metafunction-oriented. The structured analysis method is the main method of the current system analysis, such as the process-oriented function decomposition method, the control-oriented event respondent method.In essence, the object-oriented method belongs to the structured analysis.The work of all the analyses in the development process are basically the same:(1)Determine all kinds of process, operation or algorithm;(2)Determine the operation exerted on the information or data of the system;(3)Determine the execution sequence of all kinds of process, operation-the overall control of the system. In the procedure of developing GIS, the idea of reuse which runs through the whole process of component development is used.As an integration mechanism of GIS, the metafunction has the following features:①good module and strong independence;②high reliability;③simple connection and application;④sealing and package function;⑤efficient realization of interior function;⑥distinct and concise explanation.According to the result of the domain analysis, we extract the basic component of the domain.Take the domain of land administration of land bureau as example, we categorize the business into the following templates:①spatial data (graphic) template;②document template;③calculation template;④statistic template;⑤system maintence template;⑥decision template.Firstly, we finish the kernel component and basic component of these templates so that we can reuse them to develop component for the special purpose. The GIS function component bus architecture model can solve the problem of mutual communication between the GIS metafunction components, support the high level communications during the process of software installation and the running of software.It can also solve the problem of cooperation between the GIS metafunction components.The variation analysis of the system is the premise of GIS function component bus.That is, the variable part of the system is made into data component.The variation of function component and interface component are fulfilled throungh the change of the data of data component.Thus, the system has the function of redefinition, and the adaptability of GIS is highly enhanced. The metafunction-oriented GIS analysis and design is one of the efficient methods of realization of function integration and self-adaptable function integration.The realization of this method will guarantee the construction of the best of system constructure and the achievement of maximum efficiency of system.The method reflects a new trend of GIS application and development which is new system-centered and merges with many advanced technologies.