  We study a stochastic model of urban growth generating spatial distributions
of population densities at an intermediate mesoscopic scale. The model is based
on the antagonist interplay between the two opposite abstract processes of
aggregation (preferential attachment) and diffusion (urban sprawl). Introducing
indicators to quantify precisely urban form, the model is first statistically
validated and intensively explored to understand its complex behavior across
the parameter space. We then compute real morphological measures on local areas
of size 50km covering all European Union, and show that the model can reproduce
most of existing urban morphologies in Europe. It implies that the
morphological dimension of urban growth processes at this scale are
sufficiently captured by the two abstract processes of aggregation and
diffusion.
