Migration, Functional Distance, and the Urban Hierarchy

origin and destination [13, pp. 49-50]. In general, the net effect of these properties may be viewed in terms of the functional distance between any two places (or nodes). If each node's (n) properties are mapped in an n-dimensional space, it is possible to compute a measure of distance separating any two nodes, termed functional distance, such that it reflects the net effect of nodal properties upon their propensity to interact [6]. In this context it is understood that lesser func-