Study And Implement On Qualitative And Quantitative Unite Query Component In GIS

Along with the progress and development of human society, people's production and life more and more depend on the knowledge of environment which circles us. Geography supply the classifying, describing, analysis and expression methord and theory of the surface of earth. Come to the Information Period, the information disposed methord have changed from traditional to informationizational, the Geographic Information System(GIS) has become a across subject between Geography and informatics. One aspect, the problem of Geography is the aim of this subject; Another aspect, the theory and technology to collect store analysis express geographic data has became the significant research issue of the new subject. therefore, it is meaningful to research the disposed methord of geographic data from the computer science perspective.Query is a manipulation that any information system can't avoid, but for the GIS, it has the geographic characteristic. It is not a query only with relation database and its attribute but also with the entity in spatial when introduce into spatial database. There are requirement of implement qualitative relation and quantitative characteristic query which based on spatial entity. The query contain topological relation query, direction relation query, measurement relation query, shape style query and so on. It put forward new requirement of theory and technology in computer science field.The thesis based on the theory of GIS subject, and it focuses on the solving from computer science. It introduced new production in computer science which concentrate on the requirement, and it emphasize the production of combinative table and hierarchy model reasoning technology on qualitative reasoning field. From such production and combine with relational database theory, it proposed a qualitative and quantitative union query system which adapt to GIS. The purpose of the research is to discover the consistency of spatial object's features and attributes, and to find a suite symbol system which can effectively describe characteristic and attribute of spatial object, and it can express complex relation in order to fix some thing which people are interested in. The query system is directed by the symbol system, based on the spatial database component and spatial relation reasoning component. It makes up of two parts and four processes—interpret part and execute part, accidence analysis, syntax analysis, semantic check and execute process. The query system has implement as ActiveX component by VC, and gives the demo system to show how to use the query component and MapX component to builde GIS. That proves the feasibility and practicality of this design. This thesis indicate the philosophic process that from theory to practice.