Research And Development On GIS Component Library Management System

With the application and development of GIS (Geographic Information System, GIS) technology, people put forward higher demands on the research and development of GIS software, especially in the areas which need the support of computer information technology (IT) to solve GIS inherent problems, for example, the areas of interaction etc. . This paper used Object Oriented technology (OO) and software reuse etc. for reference, advanced and basically realized GIS reusable component library (RCL) management system suited for GIS field.The system's structure has three tiers: data tier,system tier and application tier. This structure is flexible, exoteric and can be expediently expanded to distributing application. From the characteristic of GIS component and reuse requirement, the paper perfects the description of GIS component: The description includes not only the basic information, but also the affiliated one which supporting reuse. Under the sustain of relational database management system (RDBMS), GIS RCL can store and manage multi-type components. Therefore it can support the reuse of higher level of GIS component. Aiming at the two key technology in GIS RCL——classification and searching, the paper discussed emphatically: Based on the Faceted Classification Scheme, GIS's spatial geographic speciality, the integrating speciality of spatial attribute and non-spatial attribute, and requirement of interaction, the paper introduces GIS components' classification system. The Faceted Classification Scheme is . On the aspect of Searching Mechanism, the system optimizes searching from database structures as well as searching algorithm: The design of database structures standardizes to 3NF; and searching system provides many search options. On the algorithm, based on filtration and extration, the paper brings forward searching cushion mechanism and the cushion table's Least Frequently Used replacement algorithm. The paper adopts OO method to analyze and design the system, and develops GIS RCL system with VB6.0, also develops the corresponding web site with ASP. If want to realize the practicality of RCL and reduce the reusing cost, GIS RCL is required to manage massive component data. In order to achieve this, the system makes the best use of the ability of RDBMS in managing the great number of data, and the Faceted Classification Scheme, Searching Cushion Mechanism put forward from thepaper. Performance testing indicts that the system has basically possessed the ability of practicality.Component library is the basic establishment of CASE (Component Aided Software Engineering), and has important effect on modern software development. This paper reflects the explorement of modern software engineering method in GIS region, forces and accelerates the research on OO based GIS software's study and systematic development.