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The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
evolved into the 4D model, namely Digital Elevation Model 
(DEM), Digital Orthophoto Map (DOM), Digital Line Graphic 
(DLG) and Digital Raster Graphic (DRG). This is an innovation 
of traditional analog city representation, which results from 3S 
(GPS, GIS and RS) technology booming. Instead of traditional 
map sheet, 3S integration and digitization map and position 
based service has become a new service platform for the 
municipal governments and for the public. Geo-information 
has been the domain direction and Geo-information provider 
became the host ID. However the surveying and mapping 
industry still holds the position of build power in the second 
digitization phase. The city infrastructure is represented in the 
form of spatial data infrastructure (SDI) and Spatial information 
infrastructure (SII), and the city in this phase called digitization 
city which is only the interim from analog to informatization 
phase. 
Informatization phase is the most important phase in the 
progress of digital city. It has been pushing and will push the 
city’s modernization and further development. In this stage the 
spatial data is the main data type, and the most attention is 
being paid on the information extraction. The product model is 
the digital Measurable Images (DMI), moreover the service is 
not only based on the digitization maps and position based 
service but also based on Location Based service. Spatial 
information infrastructure (SII) and spatial grid information 
(SGI) are two formats of city Infrastructure. With more spatial 
information, more understanding, urban planning, the 
construction and the management have stepped into the 
scientific, effective and sustainable development phase. 
However Geomatics service and Geomatics providers has 
become the host ID and build power of digital city and spatial 
information technology leading the direction of digital city 
progress. The representation of the city in the informatization 
phase is further developed into a digital format from digitization 
format. 
The forth phase Knowledgement phase of city is a further 
advanced stage of the city representation. Knowledgement will 
play an important role in this phase to promote digital city 
development. Grid data is the main data type of this phase and 
Global Information Grid and Online Intelligent are the domain 
characteristic which provide Routine Based Service. More 
advantage for the municipal governors and the Public will be 
gained from one stop online server. Knowledge Industry will 
orient the digital city to the Grid city. Infrastructure spatial 
Grid infrastructure (SGI) and Spatial Service Infrastructure (SSI) 
will be online, data-sharing and interoperational basic 
infrastructure of city. 
With the most important characteristic of Ecology concept, 
Ubiquity phase will come out following Knowledgement phase 
and it is the most advanced phase. Data type is Eco-data, and 
integration of data, information and knowledge will be its most 
interesting features. In this phase the product model is the real 
time ecological data to provide ecology-based service which 
will answer when, where, what object and what change (4W) of 
city to anyone, anything, anytime and anywhere (4A). In this 
phase digital city direction is oriented towards the prediction of 
the future. Spatial Application Infrastructure (SAI) and Spatial 
Service Infrastructure (SSI) are the main framework of city 
infrastructure. Social Demand will be the key driver of Build 
Power. At this stage Eco-city will be the representation of city. 
Each phase of digital city inherits and future develops of 
previous phase, but not a simple substitution process. The 
representation of the city evolves from archive to digitization 
city, and further to digital city, its future representation will be 
in grid and ecology. 
5. CONCLUSION 
Digital city is an integrated place where we work, study and 
live. This place is characterized by high efficiency, 
convenience, security and comfort. Digital City can maximize 
the city’s strength, improve its social environment, sustain a 
rapid economic development, increase the cultural and living 
quality of people, and promote national sustainable 
development. Therefore in order to improve the sustainable 
development of the society, we must quicken the 
implementation of digital cities. The organic synthesis of 
mechanism, technology and service decides the degree of 
smoothness in the construction of Digital city. The extended 
application domain and the increment direction of the 
Geomatics depend on the services it provides, and this 
procedure is dynamic, with other characteristics such as real 
time etc. In order to provide best geo-services to as many as end 
users as possible, this paper discusses the significance and the 
strategic prospects of digital city. The orientation of digital city 
is researched in detail. Both are research topics in academic as 
well as in industrial communities. The authors probe into the 
architecture of digital city according to its development trend. 
At last, we compare and analyze the five phases of digital city 
comprehensively. We believe this will helpful for the 
integration of Geomatics and other technologies. Digital city 
will play a central role in the sustainable development with the 
help of spatial information grid. 
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