ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001
190
APPLICATION OF 4D AND ASSOCIATED ENABLING TECHNOLOGIES
FOR URBAN DECISION SUPPORT SYSTEM
RongLIU 1 ' 2 Penggen CHENG 12 ZhuguoXING 2 Kaiyun LU 2
1. National Laboratory for Information Engineering in Surveying,
2. Mapping and Remote Sensing, WTUSM, Wuhan China, 430079; Email: cpg@rcgis.wtusm.edu.cn
3. East China Geological Institute, Fuzhou, Jiangxi, China, 344000, Email: jr@ecgi.jx cn
Key words: 4D products, flood risk analysis model, virtual reality (VR), cybercity. UGIS
Abstract
With the growth of cities, both in population and area extent appears as an inexorable process. Urbanization has profound impacts on
traditional urban planning and management. In order to meet the need of scientific management city, the best way is creating urban
decision support system (UDSS). This paper presents the application of 4D and relevant technologies for UDSS and it contains four
sections. Firstly, the contents of UDSS are introduced. Some advanced technologies such as 3D city model and cybercity with virtual
reality (VR) environment for UDSS are outlined. Secondly, traditional urban planning and management bases on two dimensions.
Problems during the existing planning process arise because of lack of 3D functionalities to analyze and visualize the 2D/3D data.
However, 4D techniques are Information resources of creating and analyzing 3D city model. The conception of 4D is described. Three
dimensional digital city model and cybercity constructed using DEM, DOM and UGIS techniques are present. Thirdly, an example of
application of 4D and associated enabling technologies for UDSS is explored. We create a flood risk analysis model. UDSS preventing
flood is becoming more and more important. Finally, some conclusions are made, and some 4D techniques application is outlined.
1.Instruction
With the growth of cities, both in population and area extent
appears as an inexorable process. Urbanization has profound
impacts on traditional urban planning and management. In order
to meet the need of scientific management city, the best way is
creating urban decision support system (UDSS). UDSS are
explicitly designed to help decision makers solve spatial problem
by providing a flexible and interactive problem solving
environment (Denshan, 1991). Such environments provide
facilities for implementing optional actions, goals and evaluating
the effects of these changes on system performance
(T.A.Arentze etc. 1994). It has been widely used in geo-analysis,
resource management, urban planning, transportation, disaster
decision-making and commerce decision-making, etc.
information resources of UDSS comes from the following:
• Total station and GPS collection in the field
• Existing map digitizing
• Photogrammmetry and remote sensing
• Internet GIS and other information
Computer science, spatial information and relevant technologies
are foundation of UDSS. Virtual reality (VR) offers new and
exciting opportunities to visualize 3D urban geographical
information system (UGIS)data. Makers and users can walk
through 3D environments, see newly planned buildings and
appreciate changes in the landscape (figure. 1). To create
multi-functions UDSS, besides information collection, advanced
technologies applied become more important.
The organization of this paper is in the following way; In
section 2, the conception of 4D is described. Three dimensional
digital city model and cybercity constructed using DEM, DOM
and UGIS techniques are presented; in section 3, an example of
application of 4D and associated enabling technologies for
UDSS is explored. A flood risk analysis model is created. At last,
in the section 4,some conclusions are made.
2. 4D and Associated Enabling Technologies for Urban
Decision Support System (UDSS)
2.1 The conception of 4D
Photogrammetry and remote sensing image has created an
urgent need for techniques for urban decision system. These
techniques have numerous applications in urban mapping, urban
planning, and other geo-information engineering disciplines and
application. However, traditional urban planning and
management bases on two dimension. Problems during the
existing planning process arise because of lack of 3D
functionalities to analyze and visualize the 2D/3D data. However,
4D techniques are Information resources of creating and
analyzing 3D city model. 4D products contains digital elevation
model (DEM), digital orthophotoquad model (DOM), digital raster
graph (DRG) and digital linear graph (DLG).They have been
widely used in UDSS to visualize model and to enhance the
interaction of the decision-maker with data and image.
Fig. 1 3D buildings model
2.2 Procedure of creating 4D
2.2.1 DTM and DEM creation
Digital elevation model (DEM) are nowadays-important
resource for many disciplines and are useful for generated digital
products such as contour maps, orthoimages, and perspective
views. The main incentive for the increasing popularity of DEM is
the ability to generate them automatically from aerial and remote
sensing image by image processing and matching techniques.
Digital photogrammetry system (DPS) is main technique for
creating DEM (figure2)
2.2.2 DOM creation
The orthoimage is created based on the DEM and the
corresponding original image. According to the theory of digital
orthorectification, the coordinates of the point projected on the
original image are computed with collinear equations based on
its ground control points. Height is interpolated from DEM. The
orthoimage can be created from one or multi-images, and
resample of gray levels can be gotten by bilinear interpolation or
other interpolation methods (figure 3).
2.2.3 DLG creation
The DLG created based on digital photogrammetric system,
scanning cartographic digitization (figure 4) and other methods.
2.3 4D associate enabling technologies for UDSS
With the rapid development of digital photogrammetry and
