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<br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />o <br /> <br />The Tasseled Cap transform has been rigorously tested and used <br />extensively in agricultural research. In 1984, Crist and Cicone applied this <br />transform to simulated TM data and found that the features produced were <br />directly correlated to the physical characteristics of agricultural fields. <br />Through this linear relationship between the tasseled cap features and the <br />actual field conditions, the results can be readily interpreted. <br /> <br />As applied to TM data, the Tasseled Cap transform disseminates six <br />bands of TM data (TM 1,2,3,4,5, and 7) into three-dimensional space. The <br />three orthogonal axes define two perpendicular planes and a transition <br />zone between them (Figure 3). Crist and Cicone (1984) identified the two <br />perpendicular planes as a soil brightness index and a greenness index. The <br />brightness index is highly correlated with bare soil. The greenness index is <br />highly correlated with LA! (leaf area index), canopy closure, and/or <br />biomass. The third band, defined by the transition zone, is related to soil <br />and leaf moisture content and is most influenced by the mid-infrared; TM <br />bands 5 and 7 (Huete, 1984). The position of a pixel within this three- <br />dimensional data space can be readily related to ground conditions. <br /> <br />,.:~:) <br /> <br />'__J <br /> <br />w <br />~ <br />Q <br /> <br />PLANE OF VEGJ;,'!'ATION <br /> <br /> <br />, <br />, <br />, <br />, <br />" TRANsmON ZONE <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br /> <br />Figure 3. Dispersion of 6-band TM data based on Tasseled Cap transform. <br /> <br />7 <br />