Comparison of reddening E(J − K_s) (left panel) and E(V − I) (right panel) determined in this study and E(J − K_s) vs E(V − I) obtained based on procedure from Pietrukowicz et al. (2015). The merged dataset used in this section is displayed with black dots. RR Lyrae variables approximately located in the X and Y plane at the position of spikes (see bottom panels of Fig. 7) are marked with red and blue markers. The green line represents the identity line.