and reports to be used in the field or as presentation 
materials. 
Summary Statistics Calculation 
The system can generate summary statistics which would 
help land managers better comprehend the situation of 
the Der-Chi area. Better management decisions can thus 
be made. 
Land Management Functions 
Several functions directly related to land management 
tasks have been implemented. 
For example, by combining land use data and zoning 
restriction data, land manager can quickly identify which 
parcels do not follow the zoning restrictions. These areas 
could then be targeted for law enforcement. 
Another example is that land within the reservoir’s 
protection zone should be purchased and land managers 
must estimate how many funds are required. Overlaying 
reservoir protection zone with cadastral data could easily 
find out how many private. properties are within the 
protection zone and the funds required to purchase they 
could be estimated. 
Conclusion 
This study has shown GIS GPS and Remote Sensing 
technologies are power tools in assisting management 
Der-Chi watershed. Remote Sensing images can be used 
to generate land use data in a cost-effective way. A 
procedure for generating land use data from SPOT 
images for monitoring land use changes. in Der-Chi 
watershed is developed. 
The GPS technology can provide accurate location in 
field investigations. To know the accurate position of 
object is important for integrating spatial data. 
Differential GPS is necessary to achieve the accuracy 
required by land management tasks. 
The GIS technology is used to integrate data from 
different agencies into an environmental database. A 
decision support system is developed based on the 
database. 
Reference 
Golby, J.D., 1991. Topographic Normalization in Rugged 
Terrain. Photogrammetric Engineering and Remote 
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Foody, G. M. et. al., 1992. Derivation and Applications 
of Probabilistic Measures of Class Membership from the 
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Maximum-Likelihood Classification. Phtogrammetric 
Engineering & Remote Sensing. 58(9). 
Hodgson, M. E., and Shelley, B. M., 1993. Removing the 
Topographic Effect in Remotely Sensed Imagery. 
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