Determination coefficient, root mean square error and mean absolute error of calibration of the machine learning regression models based on published vegetation indices.

Rc2, RMSEc and MAEc represent determination coefficient, root mean square error and mean absolute error of calibration respectively. R, 1/R, logR, R1/2, R′ and R′′ represent original spectra, reciprocal spectra, logarithmic spectra, square root spectra, first-drivative and second-derivative spectra respectively. AdaBoost, ET and RF represent Adaptive Boosting models, Extra Trees models and Random forest models respectively. (XLSX)