Application of Semantic Data Model for Geographical Information System

　　　　　本文旨在提出運用語意資料模式建立地理資訊系統的新方法。這方法包 括兩個步驟:(1)地理資訊系統的加構層以語意資料模式走立;(2)相對應的實體層 則以已商業化的關聯模式建立。故本文亦提出語意資料模式與關聯資料模式的轉 譯器。本文所提方法的優點包括:(1)語意資料模式對資料庫架構層所提供的摘要 說明能力比關聯式資料模式強，故實體資料獨立的觀念更加強化:(2)模式轉譯器 提供資料庫設計自動化的工具:(3)地理資訊系統的實體層採用功聯式資料模式以 配合目前正實際運作中的系統可持續使用。
　　　　　This paper proposes a new technique to setup a geographical information system (GIS)using the Semantic Data Model (SDM). The proposed technique consists of the followingtwo steps. First, a GIS is constructed by the semantic data model at the conceptual level;Second, the physical level of the GIS is planted on a commercialized database system of relational data model (RDM). A model translator from SDM to RDM is also designed in thispaper. The advantages of the proposed technique are: (1) the semantic data model providesmore data abstraction primitives for the conceptual structure of a GIS than are provided bythe relational data model; the concept of physical data independence can be enhanced; (2)the proposed model translator provides a valuable software tool for database designer sincethe problem of model transformation between the SDM and the RDM is solved automatically; (3) the physical layer of GIS using relational data model will accommodate the existingfact that the current operating GIS has to be in use continually.