1.2.3 Linear Combination and Optimized Indices
Linear spectral band combination indices are also widely used to measure foliage
greenness and water status (Gobron et al. 2000; Huete and Glenn 2011). The
Tasseled Cap (TC) greenness and wetness indices, as well as the perpendicular
vegetation index (PVI) and spectral mixture analysis (SMA) schemes, are all
Fig. 1.3 a Vegetation index isolines representing NDVI, SAVI, and PVI in NIR-Red crossband
space. These lines are diagrammed over the triangular cloud of crop canopy spectral
measurements (cotton, corn, wheat) over a growing season. The numbers on top and right side
are simple NIR/Red ratio and NDVI values of their isolines. b Vegetation biophysical isolines of
constant LAI (symbols connected by solid lines) plotted alongside NDVI isolines (dotted). The
NIR- Red reflectances for varying LAI were derived with the SAIL model. Each biophysical
isoline has an NIR-intercept and the soil line is estimated by the LAI = 0.01 case.
Ó [2000]
Adapted and reprinted with permission from Yoshioka et al. (2000)
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A. Huete et al.