The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
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database setup, update and mapping. For database setup and 
update, the meta-information primarily concerns about the 
geometry and attributes, while for cartography, it refers with the 
line and the filled colour, the line width, the symbol pattern, the 
placement angle of the point symbol, etc., which is useful for 
map displaying and printing out. In other words, the scheme can 
be regarded as a data dictionary. 
As to the selection of the database type of the scheme, there are 
mainly two aspects in need of consideration: one is the 
operational flexibility and simplicity for scheme maintenance, 
while the other cares about the convenience of interoperability 
between the scheme and the indoor working environment. 
Commonly, one of the most considerable strategies is to 
organize the scheme in the form of an Access database file, a 
simple small database composed of several relation tables 
which are interrelated and linked with each other, and within 
such a database are all the meta-information organically 
contained. A visualized tool for scheme configuration is 
recommended to be designed and applied in practice, to make 
the maintenance more visible, direct, reliable and easier to 
handle with. Overall, the scheme configuration is an 
independently preliminary work due to important role of the 
meta-information it records. While the image-based GIS 
database update work is carried out, the scheme is 
synchronously linked and integrated to the indoor update 
procedures with relevant database techniques. For a designed 
update system, most of the procedures need the scheme to finish 
the operation regularly, such as (1) Creation of the graphic and 
attribute template of indoor working file; (2) Structure 
reorganization of the exiting GIS database; (3) Collection, 
editing of terrain and relief data; (4) Layer management in both 
geometry and attributes; (5) Process quality control and data 
check; (6) Product exportation; (7) Mapping and printout and so 
on. 
3. CASE STUDY 
Geomapupdate is an integrated software system exclusively 
servicing the current GIS database update business of our 
country and supported by National Geomatics Center of China 
(NGCC) and designed by the research group of State Key 
Laboratory of Information Engineering in Surveying Mapping 
and Remote Sensing (LIESMARS) Wuhan University. It is a 
successful case study for the practices of integrative updating 
concept emphasized above, which has been witnessed in the 
1:50000 GIS database update business of our country recently. 
3.1 System application environment 
The system application environment is: (1) Hardware: common 
personal computer with stereo display card; (2) Stereo model 
observing equipment: stereoscopic glasses or red-green glasses; 
(3) Import equipment: common mouse with trolley or 3D 
mouse; (4) Operating system: Microsoft Windows 2000 or 
above; (5) Indoor update working environment: MicroStation 
V8. 
3.2 System framework and realization 
The image-based update is not simply a digitized process based 
on the reference images, which is more or less different from 
the pure process of data collection and editing (Ramirez 1997). 
It puts more emphasis on data integration and the incremental 
update; therefore, several key issues should be concerned in 
constructing the system framework. In terms of the function 
aggregation, the designed system is organized with six modules 
respectively servicing for: (l)data preparation, (2)indoor 
collection and update, (3)field invalidate and supplement, 
(4)quality control and check,(5)product export, and (6)scheme 
maintenance, each of which consists of many related functions; 
in terms of the implementation environment, the whole system 
is generally composed with three subsystems: (1) the data 
preparation subsystem, (2) the indoor update system and (3) the 
field investigation subsystem. They transfer, share data and 
information seamlessly with each other, by which the very 
sound capacity of function interoperability is gained for the 
whole system. 
Data preparation subsystem: It is independently 
developed under the Visual C++6.0 IDE (Integrated 
Development Environment) with technologies of COM 
(Component Object Models) and other ActiveX controls, and 
the main user interface is as Figure 3(a). Apart from the 
uniformly projective management of various datasets, the 
subsystem also fulfils the settlement of the environmental 
parameters, the multi-data conformity as well as change 
analysis. Overall, it provides a comprehensive framework of 
datasets for the subsequent indoor update and field investigation. 
Figure 3. The main user interfaces of the three subsystems 
Indoor update subsystem: it is developed based on 
platform of MicroStation and constitutes the core part of the 
entire system for update, which aggregates powerful and 
efficient function modules, such as the module of indoor 
updated data collecting and editing, the module of layer 
management of the working file, the module of attribute 
information administration, the module of quality control and 
check, etc. As one of the currently mainstream CAD 
(Computer-aided Design) software systems, Bentley 
Corporation’s MicroStation is an innovative CAD platform 
used by teams of architects, engineers, contractors, and GIS 
professionals to integrate work on buildings, civil engineering 
projects and geospatial information 
(http://www.bentley.com/en-US/Products/MicroStation). 
Its powerful capabilities in aspects of drawing, symbol making, 
data manipulating and program developments continuously 
expand the application fields including GIS in recent years 
(Schutzberg 2003). Therefore, the indoor update subsystem is