Morphological coherence (MD and ER) versus Spatial position. All open circles (representing the sample clusters), all black error bars (being the errors of the MD or ER), and red curves (denoting median filter lines), same as those in Fig. 7. “GC” and “DR” represent the Galactic center and the Galactic differential rotation, respectively. (a) Distributions of the MD of the sample clusters with their spatial location. (b) Distributions of the ER of the sample clusters with their spatial location.