2.5 Network-based risk index
SNA parameters values at the premise-level (Degree, Betweenness, Closeness and the reverse PageRank) were aggregated at the municipality level to visualize spatial hotspots of movement. As a network-based spatial risk index, we re-scaled all network metrics from zero to one, and then summed across all premises to generate the raw risk index and visualized a municipality-level risk map. To calculate the index, we summed the values for a specific SNA parameter (SNP ) in the municipality as (eq. 6)