Comparison between synthesized radio maps for a uniform B at an age of 1000 yr (black, green, and red dots for quasi-parallel, quasi-perpendicular, and isotropic injection efficiency, respectively) and the observed radio map (black diamond, the inset shows a zoom of the plot around this point) by means of the use of the A and C morphological parameters introduced in Fig. 2. Each curve represents the values spanned by the parameters when the aspect angle φ_B goes from 0° (rightmost part) to 90° (leftmost part).