# Figure 3

 Nominal versus measured displacements in the horizontal (left) and vertical (right) length-scale calibration scans. Data are represented by symbols, while a linear fit is represented by the solid lines. The uncertainties are smaller than the symbol sizes. The blue (green, red) lines and solid circles (triangles, squares) correspond to a nominal displacement step size of 21.06 $\mu$m (32.43 $\mu$m, 42.16 $\mu$m).