Fig. 4

TransCode of the third wave (period 2) of COVID-19 outbreaks in Hong Kong, China. a The daily case numbers from January 23, 2020, to February 14, 2021, in Hong Kong, China (top left); period 2 is highlighted in pink. The district-level TransCode (i.e., the transmission network, which is shown as matrix) of period 2 (bottom left). The constituency-level TransCode of two representative districts [Yau Tsim Mong (E) and Wong Tai Sin (H)] (right). Darker colors on the matrices indicate higher case numbers within the district/constituency and higher transmission intensities between the districts/constituencies, respectively. b Chord diagram of the TransCode at the constituency level. The outermost bar charts show the cumulative case numbers in the 452 constituencies. Next to the bar charts, the two-layer heatmaps illustrate the exported (outside layer) and imported (inside layer) disease transmission intensities of each constituency, respectively. Red indicates high transmission intensity, and blue indicates low transmission intensity. Next to the heatmaps, the inner circle of the chord diagram is divided into 18 pieces, each a different color, representing the districts. The innermost connections show the disease transmission between different constituencies. The color of the edge shows the district to which the constituency belongs, and the width of the edge denotes the transmission intensity. Yau Tsim Mong (E) and Wong Tai Sin (H), two representative districts, are enlarged on the top right and bottom right, respectively