區位與環境資訊是不動產買賣雙方最重視的資訊，但消費者卻往往不得其門而入，透過網際網路三維地理資訊系統為基礎之仿真數碼城市，可以提供消費者這方面之客觀且量化的資訊，這有助於減少不動產之買賣糾紛。惟三維空間資料量太過鉅大、網際網路狹窄的頻寬、伺服器有限的運算能力與客戶端顯示效能的不足，使得在Web 3D GIS平台實現仿真數碼城市顯得困難重重。有鑒於此，本研究採用GIS三維模塑工具施行建物重建，並提出多尺度建物模塑策略。該策略是依照建物之重要性與相對於主要道路的位置，以不同尺度來建置房屋模型。該成果顯示，空間資料量大幅降低，網路上資料傳輸的效能因而提升，在經濟面上成本大幅降低，從而實現其在Web 3D GIS的可行性。本研究進而建置不動產區位與物理環境查詢系統，應用環域分析工具獲得區位資訊，應用日照模擬、視野分析、地勢排水和海平面上升等GIS空間分析工具獲得物理環境資訊，研究成果顯示，透過這個查詢系統可以提供消費者相關於不動產之區位與物理環境之量化資訊。

Both location and environment information are the key reference for either buying parties or selling parties in real estate market, however consumers acquired them hardly. It will provide consumers the information, by objectivity and quantity, through photo-realistic cyber city based on Web 3D GIS. Due to large amount of geo-spatial data, narrow network bandwidth, limited computation ability of server, and non-superior performance of client, it is so difficult to perform the photo-realistic cyber city on Web 3D GIS server. Thus, at the beginning, a multi-scale building modeling based on GIS 3D modeling tool is proposed in this study. The degree of scale for a certain building is decided according to its importance and relative location to a major road. The result showed the geo-data volume was decreased largely, and the efficiency during data transfer on the Internet is increased, and the cost in production was also reduced, and therefore its applicability in Web-based 3D GIS is raised. In real estate applications based on the designed Web-based 3D GIS platform, a location and physical environment query system to assist users to choose the optimum house has been thus established. It applied buffer-zone analysis tool on location queries, and other GIS spatial analysis tools, i.e. shadow, view-shed, terrain-profile and sea-level rising analysis, on physical environmental queries. The result showed users can obtain the location and physical environment information of real estate in quantity via this query system.