Human mobility data in the COVID-19 pandemic: characteristics, applications, and challenges. - Tao Hu 004; Siqin Wang; Bing She; Mengxi Zhang; Xiao Huang 003; Yunhe Cui; Jacob Khuri; Yaxin Hu 003; Xiaokang Fu; Xiaoyue Wang; Peixiao Wang; Xinyan Zhu; et al. (Int. J. Digit. Earth, 2021)