Spot positions were allowed to migrate around a 21 × 21 box centred on the original predicted position. The pixel shift in X and Y coordinates from the original starting point was retained for each reflection. These pixel shifts were aggregated for each panel. The X and Y pixel shifts of each reflection on a single panel were plotted against each other, as above. The average intensity counts were calculated for each panel. Green reflections are those below the average, whereas blue reflections are those above the average intensity. (a) This panel is the third panel from the left and five panels down from the top of the detector. The most common shift in this panel was easily resolved. The applied shift for this panel was (−3.2, 4.4) pixels in X, Y coordinates. (b) This panel is the second panel from the right and five panels down from the top of the detector, plotted at an incorrect detector distance to show streaking along the X axis, but the most common shift could still be resolved and was at (0.2, −0.5) pixels. Because the data were weaker than those in (a), more spots incorrectly focused on noise and deviated from the common shift of (0.2, −0.5).