“…On the whole, all provincial-level administrative units have related MV released and disseminated. Among them, the central and eastern regions are darker in color, and the western and northeastern areas are relatively lighter, which coincides with the "Heihe-Tengchong Line" [22]. To be specific, four provincial-level administrative units, including Beijing, Shandong, Guangdong, and Henan, have the darkest color.…”