In recent years the global nature of epidemic spread has become a well established fact, however there have been limited studies on the detailed propagation of infectious diseases on regional scales. We have recently introduced a simulation program that explores disease propagation on such scales: the model uses a gridded geographical description of human settlements on top of which mobility is implemented using the Radiation Model. Parallel computation permits unlimited complexity. Both individual and equation based simulations of epidemiological models can be performed, thus permitting the exploration of the effects of mobility locally and globally. Using a SIR model parametrized for measles, we perform simulations for the area of British Isles, which we assume isolated. Exploring how the dynamics is influenced by human mobility, we show that mobility influences the dynamics globally and locally. In particular, the interplay of mobility and city size, enhances or reduces the contribution of the different mechanisms involved.