Maxime Colomb is defending his PhD thesis entitled "Multi-scale simulation of realistic forms of residential development from the parcel to the metropolitan area". 

The defense will take place at the Université Paris Est, in the IGN (Institut Géographique National), 73 avenue de Paris, Saint Mandé on September 27th, 2019.

This work was directed by Julien Perret, Senior researcher, IGN (French national Geographic Institute) and Cécile Tannier, Senior researcher at CNRS (French National Centre for Scientific Research), Laboratoire ThéMA and co-directed by Mickaël Brasebin, Research Officer, IGN.

Defense jury

Cyrille Genre-Grandpierre, Professor at the University of Avignon, France

Jacques Teller, Professor at the University of Liège, Belgium

Hélène Houot, Lecturer at the University of Franche-Comté, France

Florent Le Néchet, Lecture at the University Paris-Est, France

Abstract

The process of urban sprawl of urban agglomerations is very often criticised for numerous reasons. The dynamics of residential developments, at the origin of urban sprawl, are very complex and result from the interaction of several phenomena. Many laws and regulations are supposed to control the construction of buildings in order to limit the negative impacts of urbanisation. It is nevertheless difficult to anticipate the effects of such a regulatory corpus. Its multi-scale nature, related to the different levels of regulation, the different regulated subjects and the different parties executing those regulations complicate the forecasting of their effects and the spatial configurations they contribute to create.

Here, we propose a simulation model for the residential development of an urban agglomeration. It produces realistic configurations respecting the orientations, goals and constraints stemming from urban planning documents. To that end, we elaborate a coupling of two existing spatial simulation models. This coupling, named ArtiScales, follows a top-down approach in simulating the shape of the residential development of an entire study area by selecting the constructible parcels and by simulating the construction potential of each plot. ArtiScales integrates the MUP-City model, that allows us to select interesting locations with respect to the built configuration of the study area and to several points of interest (transportation networks, shopping facilities, services, etc.). We develop a parcel management model in order to select the existing parcels interesting for residential development and to recompose them when needed according to the chosen scenarios and to specific situations (densification, special operations). Finally, we use the SimPLU3D model to simulate the constructibility of each parcel. This model generates spatial configurations, in three dimensions, respecting the regulatory constraints originating from the local urban planning scheme (Plan Local de l’Urbanisme - PLU). We concentrate the analysis of the coupling results on the estimation of created housing units and its agreement with the goals defined by the local housing program (Programme Local de l’Habitat - PLH) and on the housing density by hectare and its agreement with the goals defined by the territorial coherence scheme (Schéma de Cohérence Territoriale - SCoT).

Spatial simulation models are subject to an important variability that questions the reliability of simulation results. MUP-City being particularly subject to such variability, we conduct a complete analysis of its simulation results in order to caracterise the parameters responsible for this variability and how it translates to the produced spatial configurations. We distinguish two types of variations : the ones caused by scenaristic parameters, allowing to simulate different residential development forms, and those caused by technical parameters (internal to the model), allowing to propose variants of the scenarios. The variability between the variants is compared with the variability found in the study of MUP-City results in order to see if the model coupling absorbs or amplifies it.

The ArtiScales model (https://github.com/ArtiScales/ArtiScales) is available as free and open source software and can be used in many applications. A set of simulations representing different scenarios has been explored on the Grand Besançon territory (East of France). Simulations carried out represent a potential for residential development conforming to all the regulations at work. We also propose simulations that modify the zoning authorising the construction or not.