Research on the Influence of Effective Distance Between Cities on the Cross-regional Transmission of COVID-19

Shanlang Lin; Yanning Qiao; Junpei Huang; Na Yan

Brockmann & Helbing (2013) proposed a new concept of distance, which believes that the spread of disease is not related to the geographical distance between cities, but is closely related to the "effective distance" between cities. What is the effective distance? The effective distance between cities is the length selected by a passenger in various selectable routes from city i to city j. A passenger can be regarded as a random walking particle, who randomly visits the surrounding cities according to the traffic flow. After arriving at the next city, it is converted into a probability to visit the neighboring cities of the next city according to the traffic flow... Finally, the path which the particle most likely to choose from city i to city j is namely the most likely path. The length of this most likely path is the effective distance. We argue that this probabilistic effective distance is related to the flow of population and the degree of transportation convenience, and can reflect the strength of the spatial connection between cities. The effective distance varies with the strength of the spatial connection. This concept is more accurate than traditional connection strength calculations based on the size and distance of the two cities, such as economic connection, market potential, and market access; it is also more accurate than simply using the population flow to characterize the connection, because it cannot express the strength of the connection between the two cities, not to mention the convenience of the connection between the two cities.