Geoscience Reference
In-Depth Information
In a general fashion, CA have given rise to many research directions in the field
of geography. Some are theoretical, relying, for example, on couplings with
microeconomics models. Others are operational and often coupled with GIS
[POR 97, BAT 05, BEN 04]. We propose to quickly introduce a few of these
experiences in order to illustrate the diversity and richness of the research possible
in this area.
Caruso
et al.
[CAR 07] integrate a theoretical model of urban economy with a
CA to explore the conditions for the emergence of a mixed belt between the center
of the city (CBD) where employment is concentrated and the countryside occupied
by agriculture. This mixed belt at the periphery of the center is composed of
residential areas, more or less dispersed, and agricultural areas. The spatial structure
which emerges, rather denser in the central area than on the outer fringe, shows
some stability in time. The model is of theoretical nature and corresponds to the case
of the monocentric city, with an isotropic space at the center of which is located the
CBD.
The mechanisms introduced in the model rely upon the results of many
econometric models applied to a diversity of cities and based on statistical models
(multiple regression and logit model notably) where the variable “to explain” is, for
example, the value of real estate property (hedonistic model) depending on the
characteristics of that property (for example, for a house: the number of rooms and
bathrooms) and the environment in which it is located (proximity to green spaces, a
train station, for example). These works show notably the attractive effect of green
spaces, whether they are parks or peri-urban agriculture. This aspect is integrated in
the model through the inhabitants' preferences. Each cell is occupied by either a
residence or agriculture. The economic model evaluates the choice of new migrants
on the basis of arbitration between the cost of transportation to the CBD and the
attraction for the neighborhood. Two components are involved to characterize this
neighborhood: the social amenity and the presence of a green environment. It is a
competitive market where the cell is assigned to the highest bidder. The installation
of each new migrant transforms the neighborhood and, thus, the conditions for the
following migrants. The simulation results show that the degree of diversity of the
urban space depends on the relative importance accorded by the agents to the social
amenities relative to the green amenities. The mixed belt emerges at the periphery of
the compact urban center when the preferences for green spaces are accentuated
[CAR 07].
Another research direction looks to develop a more empirical approach, in
particular, by seeking to adapt the CA to a realistic geographical space. Putting
forward the nonlinear perception of distances, van Vliet
et al.
[VAN 09] extends
Engelen and White's work by proposing scalable neighborhoods, the size of the
spatial units qualified as
neighboring
varying as a function of their distance to the
