International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B4, 2012 
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 
efficiency will be dependent on the integration of these 
procedures in the same system. So, a practical system must be 
powerful in the integration of geo-spatial database updating. 
(4) Visual simulation of traditional generalization work 
environment 
This point focuses on the links of traditional paper maps and 
digital work environment. In traditional way of paper maps, 
many generalization procedures have been used for many years, 
and become customs of human operators, so the new digital 
updating environment should have a good links to the 
traditional environment. For instance, in the visual environment, 
the larger scale geo-spatial data can be viewed as "a paper map 
of updating source" to be placed on the bottom of the smaller 
scale old data as transparent display. 
3.2 Basic principle 
Theoretically, geo-spatial updating based on map generalization 
is mainly dependent on two kinds of critical technologies: map 
generalization and change detection. Possible change 
information can be detected with change detection, while the 
new updated data can be generated with map generalization. 
Both of them are consisted of the core technologies for the geo- 
spatial database updating. Generally, geo-spatial database 
updating can be described as the following: matching the larger 
scale and smaller scale data and making overlay analysis to 
detect all possible changes; then selecting change information 
from larger scale based on map generalization rules , 
simplifying the corresponding features, detecting conflictions 
between features; finally checking data quality and updating the 
old smaller scale database. Figure.1 shows the basic principle of 
geo-spatial database updating. 
        
    
     
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Figure 1. Basic principle 
3.3 Technical work flow 
According to the principle described above, the technical work 
flow of geo-spatial databases updating can be designed as fig2. 
The main steps includes as follows: (1) acquire updating 
sources; (2) analyze the data source and determine whether they 
can be used; (3) pre-handle larger scale data, including format 
transformation, map projection transformation and edge 
matching and so on; (4) integrate all used data source into a 
visual environment and make overlay analysis; (5) detect 
change and extract change information with the aid of image 
sources; (6) apply map generalization operation edit the smaller 
scale data with change information derived from larger scale 
data; (7) detect possible conflictions between updated features 
and resolve them; (8) update the smaller scale data and record 
the changed information. 
  
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4. IMPLEMENTATION 
4.1 System development strategy 
According to the design described in Section 3 and the practical 
requirements in a given satiation, a corresponding System can 
be developed to perform the task of geo-spatial database 
updating. Currently, some commercial softwares have 
developed some generation operators, but there are no mature 
commercial software used for geo-spatial database updating 
based on map generalization. 
Therefore, it is a better choice to adopt an integrated strategy 
for developing such system, i.e., utilize a part of functions of 
map operators or visual environment provided by the 
commercial softwares, and develop the other parts based on 
component object technology independently. 
4.0 Implementation 
In order to meet the practical requirements of National 1:50000 
geo-spatial database updating, a system is developed and 
implemented according to the above design and development 
strategy, shown in Figure 3. 
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