Efficiency of ETM+ Data Analysis to Determining of Suitable Vegetation Indices (Case Study: Vazrud Watershed)

In this study Landsat ETM+ (2000/7/18) and field data were used to assess the vegetation indices of grasses, forbs, shrubs and bushy trees canopy cover which investigated in mountainous area of Vazrud watershed. Sampling techniques in this study were randomized and field investigation by 360 collected quadrates in 34 units. Global Positioning System (GPS) device was used in order to adjust the used pixels to the ground control points. Pre-processing on satellite data such as geometric corrections were implied based upon the digital maps at 1:25000 scales. In order to gain the vegetation indices the correlation coefficients were determined between dependents variables of species and indices, as the independent in SPSS software environment. The extracted results from this study indicated a significant correlation between Landsat ETM+ different bands and vegetation groups. The highest correlation was related to the band 4 ETM+ with grasses canopy covers (r= 0.43), as well as band 5 with shrubs (r=0.36). The highest rate of correlation in respect to the indices identified for the vegetation cover such as Infrared Percentage Vegetation Index (IPVI) for forbs cover (r=0.60), Visible Atmospherically Resistant Index (VARI) for grasses cover (r=0.45), MSI (Moisture Stress Index) for shrubs cover (r=0.39), MIRV1 for bare soil (r=0.37) and finally for the vegetation cover generally (r=0.36). Finally the results showed that the ETM+ bands are recommended as suitable sensors with high efficiency for discrimination of different land covers, using vegetation indices.