A Preliminary Review on 3-dimensional City Model

Modern city system has increasingly become more complex in spatial context, with impressive 3-dimensional features shown on its skyline, such as high-rise buildings, road flyovers, tunnels and underground infrastructure. Focusing on such complex system, Urban GIS, traditionally only concerns about 2-dimensional spatial relationships, has now pushed to analyse, model and manage the 3-dimensional features of the modern urban system. Although numerous works have been reported on the development and applications of 3D city models, which form the foundation of 3D Urban GIS, they mostly serve for visualisation and presentation purposes. Such 3D data models are not capable of dealing with problems of spatial queries that rely on topological relationships, nor can they provide adequate spatial operators for 3-dimensional spatial analysis. This paper outlines the findings of review on 3D City Model (3DCM). Through the review of existing works on the 3DCM, one may argue that almost no existing model that is optimised for modelling today’s 3D cities, although they do serve for specific design purposes well (e.g. visualisation and urban landscape planning). To adequately handle management problems of modern 3D cities, an alternative approach is suggested, by integrating the concepts and techniques of Object-Oriented (OO) GIS with those of Computer Aided Design (CAD). This research pays particular attention on defining and formulating topological relationships between complex spatial objects and corresponding fundamental spatial operators. It is believed that the models developed in this study will form a solid foundation on which applicable 3D urban GIS can be built.