Figure 3.

The presence/absence (1/0) of (a) airports and (b) railway stations in prefectures, and the distributions of (c) arrival days and (d) peak days for prefectures. The green line in (c) indicates the Heihe-Tengchong (Hu) line, and the one in (d) indicates the Hukun Railway that connects Shanghai and Kunming. The arrows illustrate that arrival days (or peak days) between prefectures with and without airports (or railway stations) are compared using the Mann-Whitney U test, and their spatial heterogeneity stratified by airports (or railway stations) are detected using q-statistic test.