Extracting Water-Body Information with Improved Model of Spectal Relationship in a Higher Mountain Area

The Namjagbarwa area in eastern Himalayas Mountain is a high undulant region,when the method of spectral relationship is used to take water-body information,a lot of shadows are taken as water-bodies with mistake,and the water-body is also easy to confuse with the ice-snow,alluvium and glacial debris.Supported by the processing technology of remote sensing image,spectral features and spectral differences of various objects in the experimental region were collected and analyzed in detail with Landsat-7 ETM+ image.The study discovers that the spectral value of the water-body descends slower than the shadow in visible light bands(namelyTM1-TM3),and the spectrum of the water-body is higher than the shadow's spectrum,and lower than the alluvium,ice-snow and glacial debris in TM3 band.On the basis of normal method of spectral relationship and all studies above,a new multi-condition model of spectral relationship with method of threshold and other new spectral relationship was built in this paper.It gained a better result to extract water-body information of Namjagbarwa area with the improved new model.