An Effective Way for Automatically Extracting Water Body Information from SPOT-5 Images

Extraction water information from remotely sensed images is signi fi cant for surveying, planning and protecting water resources. In this paper, taki ng Dama county of Tongxiang city as a case study area, SPOT- 5 image collected on Aug, 2002 was used. The approach of extraction is discussed. Firstly, the spe cial band(PRWI) was applied to extract mixed water and residential information. Secondly, the mechanism and characteristics of water bodies and other objects in SPOT- 5 imagery is analyzed to find the possibility of extracting farmland fro m the background. The results show water bodies are distinguishable form residen tial information in SW band and IR band. Thirdly, based on the analysis, a simpl e model of decision tree is applied to extract water information. Finally, the r esults are checked by visual and statistical accuracy assessment. The results su ggest that the model of decision tree is simple and effective and much higher th an the supervised classification's. However, some pixels in the neighborhood bet ween water bodies and mulberry are judged by mistakes.