Pl-7-6 
ACKNOWLEDGEMENT 
This study is research is funded by “Research for the 
future” program of Japan Society for Promotion of 
Science. 
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Lu, M.,et.al,(1995): Computation of Hydrologically 
Sound Grid-based DEM from Contour Lines 
Considering the Position of Valleys and Ridges, Voi. 
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Nogami,M.(1998): An Algorithm and a C-Program 
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Theory and Application of GIS(J. of GIS Association 
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