Scatter in log (GDR) as a function of X_CO and K_dark. The color scale and solid white contours indicate the amplitude of the scatter in log (GDR) as measured by the standard deviation for varying X_CO and K_dark offsets. Radii between 0 and 1 kpc (top), 1−2 kpc (middle), and 4−5 kpc (bottom). The white cross corresponds to the minimum scatter (i.e., best fit). The contours correspond to constant scatter values and give an indication of the uncertainties and degeneracies. The white lines correspond to constant GDR values of 100 (solid), 150 (dashed), 200 (dotted), 250 (dash-dotted).