In this paper, advances of the research project “Computational modelling and simulation using Geographical Information Systems (GIS) with system dynamics applied to epidemiological phenomena” are presented. Specifically, a model to describe the critical factors in the propagation of epidemics is introduced. The model integrates the most common mathematical models used in epidemiology (SIR, SIRS, SIS) with georeferencing and simulation using different computational techniques. Pondered weight techniques are employed in the solution of a case study (asthma epidemics in New York).