Roland Billen
INTRODUCTION OF 3D INFORMATION IN URBAN GIS : A CONCEPTUAL VIEW
BILLEN ROLAND
Aspirant FNRS (Fond National de la Recherche Scientifique — National Foundation for Scientific Research),
Laboratory SURFACES, Department of Geomatics, University of Liege, Belgium
Roland.Billen @ulg.ac.be
KEY WORDS: 3D GIS, Urban objects, Modeling.
ABSTRACT
This article shows the basic effects of the integration of 3D information in urban GIS. It presents from a user point of
view the reasons why 3D information is not widely used. This study is only conceptual and is free of any technical
constraints. The underlying statement is that, in a first approach, all urban phenomena should be considered in 3D since
the urban physical environment is in 3D. The reasons not to model in 3D are technical or conceptual. When no more
technical limitations will remain, only conceptual justification will be put forward. It means that the third dimension
should be disregarded only if it is not relevant. The lack of 3D thought due to the inheritance of the “old” 2D
information structures, is reported as a major inhibition factor. Therefore, some means such as the use of well defined
urban objects with strong relations, are provided to help the user to evolve from a 2D to a 3D spatial thinking. The
impact of this evolution on GIS conception method is discussed. Thus, the user could design a complete conceptual
model of his 3D virtual world. He would have a powerful tool in order to choose the optimal 3D data acquisition mode.
Afterwards, the setting up of a global 3D urban model with different subdivisions is discussed. The underlying idea is to
provide a common 3D model which can be used by different users. This follows the same goal as the actual 2D urban
databases provided by public authorities.
FOREWORD
This contribution should be seen as a first doctorate report where the basic study framework is defined. This article
presents concepts that are not related to any data structure or acquisition modes. It is free of any technical contingence
and must only be read at a conceptual level. The complete study is planned to tackle 3D structures and acquisition
modes and will be achieved by the concrete implementation of a 3D urban GIS. In a primary approach, it seemed
necessary to focus on the basic concepts. This prerequisite was more complex than expected. It took a fundamental
character and is becoming the primary interest of the doctorate study.
1 INTRODUCTION
The 3D modeling of the urban environment is a major issue for a wide range of scientific research. This specific
research focuses on the basic effects of the integration of 3D in urban GIS, or, to be more precise, on the evolution from
a 2D to a 3D spatial thinking. This article tries to understand why the use of 3D information is actually so unusual. A
user perspective is taken. The ultimate aim is to provide tools to ease the evolution from a 2D to a 3D thinking.
2 INTRODUCTION OF 3D IN URBAN GIS
The introduction of 3D in urban GIS is often view through its technical aspects. At a first glance, it deals with 3D data
structures for 3D processing, especially visualization, and with 3D data acquisition modes. Even if 3D is known to have
an influence on different phenomena most of urban specialists don’t use 3D information, except for a few town
planning applications and for pollution studies. In their survey on 3D-city models Fuchs et al. (1998) argument to
explain the fact that only few institutions are using or producing data in 3D that the cost for the acquisition is still high
and that the users requirements are not really known. The later reason should be investigated. Are producers ignorant of
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B3. Amsterdam 2000. 79
