Formulas of several commonly used vegetation indices.

Note: B, R, NIR, and SWIR are the surface reflectance in the blue, red, near infrared, and shortwave infrared bands, respectively. SWIR_max and SWIR_min are the maximum and minimum surface reflectance in the SWIR band, respectively. SWIRmax and SWIRmin are defined as the 1% minimum and maximum cutoff points in the histogram of the SWIR band reflectance here. a and b are the slope and intercept of the soil line, respectively. L, X, Y, and Z are soil background adjusted factors. γ is an atmospheric self-correcting factor which depends on aerosol types.