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The 3rd ISPRS Workshop on Dynamic and Multi-Dimensional GIS & the 10th Annual Conference of CPGIS on Geoinformatics
Chen, Jun

ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001
Qing ZHU, Deren LI, Yeting ZHANG, Hanjiang XIONG
LIESMARS of Wuhan University, 129 Luoyu Road, Wuhan 430079, PR.China
Tel/Fax: +86-27-87643969 E-mail: zhua@rcais.wtusm.edu.cn
Key Words: CyberCity, GIS, LOD, Integrated Databases
The construction of CyberCity requires 3D city models with realistic material or texture description and related attributes and to provide
GiS’s spatial query and analysis functions. After introducing the architecture of CCGIS, the 3D modeling method based on different
LOD(level of detail), integrated databases management including the OO database model of integrated three Databases (DEM, DOM
and DLG), and the platform for 3D visualization are presented. The initial version of CCGIS had been used for a few pilot CyberCity
projects , such as ShenZhen, Shanghai and Beijing. The modeling methods and data model adopted in CCGIS are good choices for
CyberCity construction.
The first section of this paper gives a brief introduction to CyberCity and then the CCGIS architecture which consists of three
components, the 3D creator and editor, the integrated databases management system and the 3D representation and visualization
platform, is presented. In the second section, the methods of 3D modeling concerned with LOD are introduced. Especially in order for
efficiently 3D data capturing and modeling, based on the object oriented idea, CCGIS proposed a feature classification and coding
scheme, according to which the 3D coded data can be sampled very conveniently using the photogrammetric workstation. On the other
hand, a TIN based algorithm can be adopted to create the multiscale 3D city models automatically with high efficiency using these
coded data (feature points and lines). The 3D creator and editor not only can create its own 3D city models from the 3D data and/or 2D
data plus height attributes, but also can import the 3D models created by 3DS or by CAD, and the 3D models also can be edited. For
example, to copy, to move, to delete, and to modify any kind of objects of the city model are convenient.
In the next section, the proper 3D data model concerned with the requirements of OpenGL based rendering are presented at first. Then
the integration of different databases like the digital elevation models, digital orthoimages and 3D city models is discussed. For
CyberCity, since the huge data volume, its proper organization and spatial database index are quite important for data retrieving. The
version of 1.0 CCGIS just provides an initial solution for this purpose, which is based on the hybrid system of relational database and file
system. But this is not ideal, because the total data access efficiency is dissatisfactory, even more, it is very difficult to maintain the
convenience and reliability of multiusers’ operation and network transmission. So it is necessary to test the integration management of
all the data related to the CyberCity using object relational DBMS like Oracle8.16, etc.
At last, an interactive visualization platform is introduced, this platform provides the choices of 3D animation or virtual cityscape, and the
visual impact can be satisfactory through modulating the various display parameters, such as zoom in or zoom out, the rotations with 3
freedoms, the field of view and the depth, the mode of walk through or fly over, and the animation route, and so on.
The general trend of future urban economy development are
globalization and informationalization, it is also the requirement
of economy globalization to realize the urban
informationalization. To develop the comprehensive sharing of
various urban resources, to enhance and to advance the urban
information construction will become the new motivity of pushing
urban to modernization. The most distinct characteristic of urban
informationalization is the construction of “digital city”. Digital city
is a technical service system of the automatic collection,
dynamic monitoring and management, and decision making
support for the urban infrastructures and the functions by means
of Hi-Tech such as GIS, remote sensing, network, mulitmedia
and virtual simulation, and so on. Digital city provides human
beings bran-new idea and modulating measures for urban
planning, construction and management, even though the
working and the life. It can accommodate and predict the change
of urban, especially the GIS’s spatial information integrated
handling and intuitionistic representation can effectively help us
to build more complete conception and modeling intuition to deal
with the complicated urban system problems. Facing with the
increasingly higher Urbanization level, it is more and more