COVID-19病例与城市人口规模的标度律及其时间演化
许刚, 焦利民, 李新虎, 肖逸雄, 宫鹏, 龚健雅

Scaling law of COVID-19 cases and city size and its evolution over time
XU Gang, JIAO Limin, LI Xinhu, XIAO Yixiong, GONG Peng, GONG Jianya
图3 美国不同日期COVID-19累计确诊病例空间分布
Fig. 3 Spatial distributions of accumulated COVID-19 cases on four dates in the United States