| The object-oriented techniques which are popular in recent years have generated a wide-ranging and far-reaching impact to every application field of computer. Object-oriented GIS has become an important research subject in GIS field.As a standard of modeling language, UML has abundant syntax and semitone. UML is expressive and concise. It is a kind of modeling language with powerful functions that is suitable for the modeling complicated system. To solve the problem of massive data and complicated spatial relations in GIS, an ideal of creating an Object-oriented model based on UML is propose. All the works can be dividing into several parts as follows:(1) In the thesis, by the Object-oriented method, the author study and explore deeply the data model of spatial object, the definition and expression of semantics, the basic relationship among objects, the basic spatial operation and topology structure, the organization of geographic data, the storage of data and the spatial index.(2) UML can provide adaptive flexibility because user can define element of his own by the extension of mechanism. The stereotype extension mechanism can ensure stronger encapsulation and reusability. The tagged value extension mechanism describes the detailed spatial relationship and the natural language accomplishes the constraint extension mechanism.(3) GIS data model and the algorithm for the research on deep: including China, as fundamental geographic information product. This article through discrete points collected data points sequence will become orderly sequences, and then build convex hull, generating TIN model. Based on the landform accelerate rendering, terrain the quadtree structure analysis and the shortest path algorithm, and precision analysis forward their own views. (4) Realizing digital terrain model analysis of data flow, are based on feature of virtual GIS conceptual model frame semantic analysis comparison with other conceptual model, eventually got prototype system design of virtual GIS graphic.(5) Through the work ahead, the sixth chapter focuses on the system when the concrete implementation the problems to be solved, including the whole system design, database design details, system function specific design and implementation of algorithm. The author prepare graphics, attribute data material, and do some previous treatment; Then realized graphic digitized, design system flowcharts, realized the GIS data model space database. |
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