On the sample map are 4 connected areas A to D with different population densities. In the center of area B a virus infection occurs (e.g. through an international airport or train connection) and propagates through area B and the neighbour areas A,C and D with different propagation speed values. The immune system of each grid member is assumed to fight against the virus according to the function V(t) = 100% * exp (-c*t) (with c = speed constant). When a predefined threshold is reached, the grid member is assumed to have lost the ability to infect neighbour members and the corresponding white dot on the map disappears (beginning in area B where the epidemic infection has started).
