The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
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and then the architecture of the system function is designed in 
the third chapter; in the fourth chapter, the integrated software 
system Geomapupdate for national 1:50000 GIS database 
update based on geospatial imageries is introduced as a typical 
case study. It is a platform exclusively servicing the current GIS 
database update businesses 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. The whole system is 
efficiently organized with several functional modules in which 
the integration concept has a detailed embodiment. It is a 
successful case study for the practice of the integrative updating 
concept emphasized above, which has been witnessed in the 
1:50000 GIS database update business of our country recently. 
2. THE OPERATION MODE OF INTEGRATION 
In surveying and mapping industry, the essence of geospatial 
images based GIS database update is: with the up-to-date multi 
source geospatial images e.g. aerial or satellite Digital 
Orthophoto Maps (DOM), Digital Raster Graphics (DRG), 
stereo image models of photogrammetric block, etc. as the 
major information sources for update, cooperated with various 
subordinate datasets such as the vehicle-collected GPS data of 
road network, data of place name, data of territory border or 
some other thematic information in the fields of irrigation, 
electricity power, communication, transportation and land use 
etc., to accomplish the topographic database update mission 
based on the existing Digital Line Graphics (DLG) data through 
the technical approaches such as image-based information 
integration, interpretation and mapping indoors, field validation 
and supplement and so on. 
It is well known that the indoor working task such as data 
preparation, image interpretation, data revision, etc. and the 
outdoor task including field validation, supplement and filling 
out are both indispensable to accomplish the whole work of 
geospatial images-based GIS database update. As mentioned 
previously, the traditional operation mode is quite defective and 
can not keep up with the current fast update command any more, 
due to the disintegrative procedures and working tools still 
equipped with. Therefore, it is of great importance and 
significance to consider the brand-new operation mode when 
the integrated workflow (see Figure 1) and software system for 
the geospatial images-based GIS database update is to be 
designed. As a whole, the integrated software system for GIS 
database update should not only be cost-effective, practical, 
customized and with high integration degree from the system 
module design aspect , but also be characterized by some 
distinguished features described in subchapters as below. 
2.1 Integration of indoor work and field work 
Relative to the disjointed indoor and field working mode, the 
operation mode of integration first of all should embody at the 
integral whole operation of indoors and field, i.e., to make a 
homogeneous operating environment where the data acquired 
indoors and outdoors can seamlessly exchange with each other. 
In order to make this concept applicable in practice, two aspects 
should be considered in system design. 
Figure 1. The update workflow with the operation mode of 
integration 
Full digitized workflow: The software system for image- 
based GIS database update needs to work in the full digitized 
mode, which means totally abandoning the outdated analogized 
field validation and supplement mode. The rapid development 
in the field of computer engineering, modem communication 
science, embedded techniques and mobile GIS technologies 
provides many approaches to realize such an integrated 
operation mode. For example, the PDA (Personal Digital 
Assistant), as shown in Figure 2 (a), is a considerable device for 
field investigation in terms of its localizability, portability, 
outdoor manoeuvrability and data transmissibility as well as its 
powerful programmability. The efficient outdoor working 
strategy can be derived to be a replacement of the traditional by 
developing a PDA-carried, GPS signal detectable function 
module for field investigation and filling out in pure digital 
from. With the internal industry updated, it can be imported into 
PDA-based field surveying and mapping subsystem, through 
the GPS navigation to do the field work verification and filling 
out. 
Applicable without need of the professional 
equipments: The system should also integrate the registration 
and editing with no need of the professional equipment; as we 
know, the traditional photogrammetric workstations such as 
Intergraph, VirtuoZo, JX4 are all unexceptionally special 
systems which need professional equipments e.g. hand wheels 
and feet wheels to support the data input; besides, these 
equipments are somewhat expensive and importable, which can 
not meet the fast data update requirements. Therefore, to put the 
integral whole operation of indoors and field into practice, it is 
really necessary to provide the more flexible working mode, 
that is, the designed software system should support some 
accessory apparatuses which are both economical and 
convenient to operate, giving a full consideration to the 
equipment portability. With the update software installed on a 
portable computer, as to image interpretation in stereo mode, at 
present, the operator just needs a 3D mouse (Figure 2 (b)) or 
common mouse with trolley (Figure 2 (c)) and a pair of stereo 
glasses (Figure 2 (d)) to carry out the stereoscopic observation 
and measurement; to a certain degree, it also decreases the 
operating difficulty for non-professional operators, such as the 
traditional field workers who are unfamiliar with the operation 
of indoor workers.