Study on the automatic extraction of water body information from SPOT-5 images using decision tree algorithm

Abstract

Extraction of water information from remotely sensed images is significant for surveying, planning and protecting water resources. In this paper, taking Tongxiang county of Jiaxing as a case study area, SPOT-5 image collected on Aug, 2002 was used. The approach of extraction was discussed. Firstly, The mechanism and characteristics of water body and other objects in SPOT-5 imagery was analyzed to find the possibility of extracting farmland from the background. The results show that water body is distinguishable from background in SW band and hase special relationship B3 (green) > B4 (SW) and B2 (red) >B1 (IR) between bands. Secondly, based on the analysis, a simple model of decision tree was applied to extracting water information. Finally, the results are checked by visual and statistical accuracy assessment. The results suggest that the model of decision tree was simple and effective and the precision of this approach was much higher than that of the supervised classification. However, some pixels in the neighborhood between water bodies and mulberry are judged by mistakes.

Keywords

• SPOT-5 image
• water bodies
• information extraction
• decision tree