Extraction Research of Remote Sensing Water Information Based on TM/ETM in Arid and Semiarid Areas

Taking TM/ETM remote sensing of Jinghui irrigation region in the arid and semiarid areas of Shaanxi province as the example, the paper evaluates several commonly used water-extracting methods, including threshold value method, water body index method and spectral relations etc. Through experiments, the paper concludes that the extracting effect of these methods in areas with artificial trails is undesirable which makes the extracted water system incomplete while extracting water body in the arid and semiarid Jinghui irrigation region, because the backgrounds of semiarid watercourses, residence areas and soils are similar. Thus, this paper brings forward a new kind of comprehensive extracting method to accurately extract the information of water bodies with (ETM2+ETM3)/(ETM4+ETM5) > 1 and a model whose tasseled cap transformation humidity component KT_3 > threshold value. The method successfully reduces the information rate of ground objects, perfectly extractes the information of anabranch and small water bodies, meets relevant accuracy demand (96.86%), and the classification result is obviously better than that of above commonly used methods.