Figure 6
From: Retrieving zinc concentrations in topsoil with reflectance spectroscopy at Opencast Coal Mine sites
Comparing the performance of calibrating Zn concentration corrected by natural logarithmic transformation based on different spectral reflectance transformation methods using RF and PLSR at four conditions concerning the entire group, clean group, low pollution group, and moderate pollution group. (a, b): entire samples group, (c, d): clean group, (e, f): low pollution group, and (g, h): moderate pollution group.
