Simulating Urban Networks through Multiscalar Space-Time Dynamics: Europe and the United States, 17th-20th Centuries

Simpop2 is a generic multi-agent model designed for simulating any system of cities.From an evolutionary theory built upon the observation of networks of cities indifferent parts of the world and over long time-periods, it has been possible toidentify stylised facts that characterise their main features and properties. Thispaper presents data-oriented simulations of two kinds of system: in early settledcountries (Europe, 1300—2000) and in countries more recently settled (the UnitedStates, 1650—2000). The model can simulate properly the general dynamics of urbansystems, at different scales of observation (general configuration and trajectoriesof individual cities). The simulations help to identify some dynamic properties thatare shared by both systems: a general growth trend and spatial expansion (producedthrough interurban competition which generates emulation towards innovation thatexplain the persistency of the hierarchical configuration); a dramatic increase ofcontrasts in city sizes since the first industrial revolution linked to the increaseof communication speed; and, a differentiation of urban economic functions producedthrough interactions between cities and innovation cycles, as industrial revolution.The model also puts forward the necessary integration of a new urban function in themodel, which represents the early emergence of global cities. Yet, beyond thesesimilarities in the evolution of all urban systems, when they are fully integrated,the model also measures to what extent the observed peculiarities in theircontemporary spatial and functional configuration depend on differences in the earlyspace-filling process between the two kinds of system.