Euclidean distances (d, given by Eq. (1)) between several models of the LB shell inner surface as a function of the maximum multipole degree (l_max). The gray dotted line compares the first and final iterations of the iterative procedure discussed in Sect. 2.2.2 and applied to the L19 data. The blue dashed line compares the final models obtained with the L19 and LE19 data. The orange and purple dot-dashed lines compare the final models obtained with the L19 and LE19 data, respectively, with the shape of the LHB from Liu et al. (2017) (see Sect. 2.5).