Interpolation and BCD plane for one star. Shown are all (D_⋆,λ₁) points for all computed vsini in the models for R = 3300 (red) and R = 9100 (blue). The chosen subgrid to analyze this observation (R = 5100 for 1′′ slit width, vsini = 150 kms^-1) is shown in black, and the surrounding triangle is indicated by dashed lines, and the barycentric coordinates to obtain the weighted parameter values are indicated by solid lines. The nearest grid point, used to associate a spectral type, represents a B7 III star.