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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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