Regional model
The regional model simulates migration and distribution of overall growth or decline of population and employment in different economic sectors. It is based on a spatial interaction or gravity model operating on a regional scale. Regions are often based on administrative boundaries, since population and employment data is available at that level. Also, these boundaries are present in people's perception of the area.
The spatial interaction model works analogous to Newton's law of gravity. Each region attracts people and jobs from each other region proportional to its own attractiveness —see below— and inversely proportional to the distance between regions. By default distance is computed as the Euclidean distance between region centroids, but this can be substituted by other measures such as distance over the road or travel times. If Metronamica is extended with a transport model generalised travel costs are dynamically used as a distance measure in the regional model.
The attractiveness of each region is modelled on the basis of population and employment in the region and nearby regions, population and employment density and an aggregation of local characteristics from the land use model. Densities are modelled as a growth model on the basis of population and employment and net migration ratios. By combining population and employment with their respective densities, we obtain figures of surface area that are allocated by the land use model.
