International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004 
  
   
} irrigated paddy from 18 May to 20 May 
REGEND 
wrigated paddy(%) 
04-13 
      
1 irrigated paddy fom 21 May to 26 May (@) irrigated paddy from 27 May 12 5 June 
20 10 0 20 Km 
  
Fig.7 Distribution of preparatory water in paddy irrigation 
paddy * 100 (%). Flooded paddy fields start from south (low 
and flat area) and shift to north (upper area). 
We can know the details of preparatory water in field 
level (Fig.8). It is easy to understand the position overlaying 
the map image. 
Fig.9 shows percentage of paddy field before preparatory 
water on 5 June 2002. Transplanting is earlier in lower and 
west side area and transplanting is not finished in upper area. 
Total area of paddy fields and flooded paddy fields are 
corresponding to statistic value. Flooded paddy fields didn't 
verify in each term. Ogawa et al. (1998) estimated flooded 
paddy field area using RADARSAT image and mask of 
paddy field area and the area estimation is corresponds to 
statistic data. Considering these references, this map would 
be high accuracy. 
5. CONCLUSION 
In this paper, we estimate the distribution of preparatory 
water in paddy irrigation using RADARSAT/SAR-C and 
Landsat/ETM+ data (four data sets) and 10m digital land use 
map. Estimated paddy field sum up on district unit is very 
202 
  
   
   
  
  
  
  
REGEND 
not irrigated paddy (&) 
63-98 
EB oo 
BE 00-264 
265-344 
  
  
Fig.9 Percentage of paddy field before prepara 
   
(Percentage = not irrgated paddy ; 
  
  
  
high relationship with statistical value (number of districts 
are 32, r’=0.999, RMSE=21.5ha, y=1.12x). Using this 
relationship, estimation of flooded paddy field area becomes 
higher (number of districts are 18, r=0.990, RMSE=29.7 
ha). 
We verified the high accuracy of estimation and very useful 
methods. Each stage could not evaluate the flooded paddy 
area, but it would be high accuracy from the total accuracy 
and study reports. 
REFFERENCE 
Fujiki T., Satoh M., Sopaphun P. and Vudhivanich V., 2001. 
Water Management Practice in Upper Chao Phraya Delta, 
Thailand - Analysis of water use in the Borommathad 
Irrigation Project-, Transactions of the Japanese Society of 
Irrigation, Drainage and Reclamation Engineering, No.216, 
pp. 1-7. 
Nageswara P.P. and Rao V.R., 1987. Rice crop identification 
and area estimation using remotely-sensed data from Indian 
cropping patterns., Int. J. of Remote Sensing, 8, pp. 639-650. 
Ogawa S., Inoue Y., Mino N. and Tomita A.. 1998. Monitoring 
  
Internat 
Here 
of Ric 
Intern 
Param 
pp.15. 
Ogawa | 
use 
Trans 
and R 
pp- 1- 
Okamot 
using 
TM, 
pp172 
Otsubo 
Mapp 
RAD: 
Engin 
Yamaga 
paddy 
Japan 
pp.16