D-statistic comparing the interpolated and the XSL spectrum for the full wavelength range, and UVB, VIS, and NIR parts separately. The colour bar is logarithmic. Histograms show the distributions of D-statistic calculated within these spectral ranges at a resolving power of R = 500. For better visualisation, the D > 0.5 points are placed into the D = 0.5 bin on the histograms.