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UIDB/04647/2020 UIDP/04647/2020 DL 57/2016/CP1453/CT0105 The Sustainable Development Goals require us to rethink spatial planning policies’ effectiveness. This article proposes a reproducible method for assessing the effect of past planning practices and simulating future land-use and land-cover (LULC) changes with a Cellular Automata model. The originality of our approach is to systematically compare observed changes in LULC with the planning rules in force over almost a century of evolution. A quasi-exhaustive database was constructed at a very fine spatial resolution for the municipality of Portimão (Southern Portugal), including the location and changes of LULC categories, and the planning rules of the corresponding time period on nine dates between 1947 and 2018. The quantified measurement of the actual effect of planning rules enables us to identify other determinants of the evolution. Findings reveal that the policies established by the local government—which aimed to foster well-planned comprehensive urban areas—were not as effective as intended. The quantified discrepancies between planning recommendations and observed evolution help to simulate which LULC scenarios could be designed to reach the expected result in future planning policies. Our assessment method could be applied in other urban and tourist regions where land artificialization exerts strong pressure on the environment. publishersversion published

For an online journal, adaptation and renewal are constant qualities, most often accompanied by small incremental improvements, and sometimes by sudden changes of trajectory. This second modality of changes observed in complex systems was readily qualified as a bifurcation in the literature on self-organization processes, and is now more wisely called a "transition" if we wish to bring about a calmer participation to the adaptations that create novelty. Cybergeo has experienced more than one ...

Urban systems are at the core of current sustainability concerns, and their study from a complexity perspective has a long history in several disciplines. We survey this literature and discuss future research directions relevant to sustainable planning, in particular the construction of integrative approaches. We finally illustrate this research program with the coupling of urban simulation models to explore trade-offs between sustainable development goals in systems of cities., Journ{\'e}es Scientifiques de Rochebrune 2022

This year, geographers from all over the world are coming to Paris to celebrate the centenary of the IGU, their largest international organization. Books published in French have already told the story of the international congresses of geography, which began in 1871, well before the creation of this institution (Pinchemel, 1972; Robic et al. 1996). The meeting of geographers is being held for the fifth time in Paris in July 2022. The work that was published on the occasion of the centennial ...

Geographers and social scientists in general are familiar with the processes that create the world order and the representation we have of it. The long history of the world could be read as an endless quest for domination, by groups using weapons, ideologies and beliefs, technologies, systems of government, an incredible diversity of forms of pressure on people's lives. Little by little, moral reflection, politics, law, and sometimes science, have helped to build rules for better living toget...

For Jean-Pierre Bocquet-Appel, spatial variations were an intermediary in a multidisciplinary reasoning to fill the gaps in our information on past populations. We are following a parallel path to overcome our ignorance of the multiple spatial interactions that preside over past and present changes in settlement systems, especially for cities that became the dominant form of human habitat. I would like to show how spatial analysis coupled with computer models that make strong assumptions about spatial interactions could reconstruct urban populations’ evolutionary trajectories. Today, emerging methods for validating multi-agent systems allow us to identify which assumptions are not only sufficient but also necessary for this reconstruction, while the incremental construction of models allows for variable granularity in the transition from the general to the local. Les variations spatiales étaient pour Jean-Pierre Bocquet-Appel un intermédiaire dans un raisonnement pluridisciplinaire pour remplir les lacunes de notre information sur les populations passées. Nous suivons un chemin parallèle pour pallier notre ignorance des multiples interactions spatiales qui président aux changements passés et actuels dans les systèmes de peuplement, en particulier pour cette forme d’habitat devenue majoritaire que sont les villes. Je voudrais montrer comment l’analyse spatiale couplée à des modèles informatiques posant des hypothèses fortes sur les interactions spatiales permet de reconstruire des trajectoires d’évolution des populations urbaines. Les nouvelles méthodes de validation des systèmes multi-agents nous mettent désormais en position de déterminer quelles hypothèses sont non seulement suffisantes mais aussi nécessaires pour cette reconstruction, tandis que la construction incrémentale des modèles autorise une granularité variable dans le passage du général au local.

Cet ouvrage est dédié à Jean-Pierre Bocquet-Appel, anthropologue biologiste, l’un des pères fondateurs de la paléodémographie en France, disparu en 2018. Mondialement connu et reconnu, il a contribué au développement de nouvelles techniques d’estimation de l’âge au décès d’assemblages de squelettes et promu la mise en place des estimateurs en paléodémographie. Il a également participé à l’émergence de la démographie spatiale et de la modélisation de type-multi-agent en particulier des agriculteurs néolithiques. Nous lui devons une avancée considérable dans la compréhension des processus démographiques liés aux grandes transitions qu’ont vécu les hommes en différents points du globe avec la découverte de la signature de la transition démographique impliquée dans le passage des sociétés d’une économie de collecte à une économie agricole. Cet ouvrage offre un voyage au cœur de sa vie de chercheur, reprenant tour à tour, dans une démarche diachronique et pluridisciplinaire, la démographie anthropologique de la Préhistoire jusqu’à la période contemporaine. Il brosse également un portrait généreux de cet homme engagé qui n’a eu de cesse d’œuvrer pour sa discipline, que ce soit à travers une approche réflexive sur l’histoire des sciences et l’épistémologie ou la transmission de ses savoirs auprès de jeunes générations. Cet ouvrage convie ainsi le lecteur à une expérience originale et innovante aux confins d’une discipline rare, la paléodémographie. This book is dedicated to Jean-Pierre Bocquet-Appel, anthropologist and biologist, one of the founding fathers of palaeodemography in France, who died in 2018. Known and recognised worldwide, he contributed to the development of new techniques for estimating the age at death of skeletal assemblages and promoted the introduction of estimators in palaeodemography. He also participated in the emergence of spatial demography and multi- agent modelling, particularly of Neolithic farmers. We owe him a considerable advance in the understanding of demographic processes linked to the great transitions that humans have experienced in different parts of the world with the discovery of the signature of the demographic transition implied in the passage of societies from a collection economy to an agricultural economy. This book offers a journey to the heart of his life as a researcher, taking in turn, in a diachronic and multidisciplinary approach, anthropological demography from prehistory to the contemporary period. It also paints a generous portrait of this committed man who has never ceased to work for his discipline, whether through a reflective approach to the history of science and epistemology or the transmission of his knowledge to younger generations. This book invites you to an original and innovative experience on the borders of a rare discipline, paleodemography.

The notion of transition appears indispensable when changes to a system require categories not used to describe the initial state of that system. Even if that initial state could be identified with precision, by determining the system’s limits in relation to its ‘environment’ and specifying its components and their interactions, doubtful points often persist in the margins of these definitions. For example, what changes should be described as ‘system state changes’ versus ‘system changes’? Si...

The preceding chapter sets out a brief overview of the different ways in which ‘transitions’ are approached in the scientific literature, from the point of view of both the natural and the social sciences. The theoretical aspects have been emphasized. The objective here is to render this concept operative for studying the changes in ‘settlement systems’ as it is possible to observe them, on the local scale of a microregion as well as on that of the planet. Ever since modern man has existed, h...

70 000 years ago, Homo sapiens left Africa to colonize the world. 6,000 years ago, he founded the first cities. Today, in the era of city networks, he is creating increasingly wide and complex metropolitan regions. From prehistory to the era of metropolises, man has occupied the earth's space in an infinite variety of ways, under the influence of a multitude of factors. How did the Bantu populate a space already occupied by the Pygmies in equatorial Africa? How were cities born in the Bronze Age? How did the pueblo society develop and then disappear in the United States? What were the effects of Romanization on the settlement of southern Gaul? How did the village system emerge around the year 1000 in Europe? This book addresses twelve major changes in global settlement formalized as “transitions”. What is a transition? How can it be identified in the empirical field? Archaeologists, historians, linguists, and geographers combine their efforts to construct, analyze, and compare models of settlement transition in world history. Observing the particular, they seek the universal. This book proposes a method for understanding the laws of human settlement in the very long term.

Introduction: one or two ‘urban’ transitions? The majority of the world’s population now lives in cities, and the expansion of this form of habitat seems both universal and irreversible. The statistical services of the United Nations predict that, before the end of the twenty-first century, more than three-quarters of human beings will be urban-dwellers. Now, cities appeared in the history of humanity only about 6,000 years ago. With their emergence, which from the beginning situated cities w...

International audience

International audience

ed : Lena Sanders; International audience

At the end of the five years of work in our GeoDiverCity program, we brought together a diversity of authors from different disciplines. Each person was invited to present an important question about the theories and models of urbanization. They are representative of a variety of currents in urban research. Rather than repeat here the contents of all chapters, we propose two ways to synthesize the scientific contributions of this book. In a first part we replace them in relation to a few principles that were experimented in our program, and in a second part we situate them with respect to a broader view of international literature on these topics., 31 pages, 3 figures, 2 tables

International audience

International audience; The new generation of Simpop models presented in this book, as well as the approach followed all along their construction and evaluation, has specifically targeted and tackled the equifinality challenge of (urban) modelling. It is presented as a progression from solving elementary generative problems to adapting models for encompassing a variety of urban situations by sharing open tools.The first chapter presents our empirical knowledge of systems of cities, and ways of summarizing their regular properties. It builds the ‘system of reference’ upon which model-building can take place. Indeed, by generalizing processes and structural properties of empirical case studies in different spatio-temporal contexts, it specifies the elements that can be forecasted (the total urban growth, the degree of differentiation of city sizes, the spatial balance of growth, etc.) and ways to do it (theories of innovation diffusion, of agglomeration economies, of spatial distribution, etc.). By asking ‘is urban future predictable’, we question the logics of urban evolution as well as the different levels of uncertainty attached to different aspects of urban growth and interactions. Identifying the possibility of prediction makes the task of modelling interesting. Identifying key features of systems of cities provides a stylized empirical ground to evaluate simulations and study alternative trajectories. Finally, identifying areas of uncertainty as leading to the processes responsible for the urban evolution calls for a multi-modelling approach that tackles equifinality in the virtual laboratory.The second chapter addresses the first step of the modelling of system of cities. It presents a parsimonious model of the emergence of cities from a homogenous settlement system. It aims to answer a very basic question: are we able to identify a simple set of meaningful mechanisms that reproduces the observed emergence of cities at the scale of thousands of years? The SimpopLocal model is an answer to this question and it raises the challenge of calibration, in order to prove that there exists a set of parameters that are sufficient to model this emergence. It also raises the challenge of formalizing what a good simulation is in terms of long-term urban evolution, in order to automate the search for this parameter set (for which there exists no empirical ways of determination).The third chapter goes beyond the possibility of finding one way of simulating the emergence of cities. It presents a new method for assessing parameter sensitivity, by looking at the necessity of each mechanism within a given model structure. Indeed, despite the diversity of solutions to the calibration challenge, are some parameters isolated, not interacting with other parameters in the simulated output? Are they all necessary, besides being sufficient? A new method called ‘calibration profiling’ was developed to validate not only sufficiency of modelled mechanisms but also the necessity of theoretical hypotheses that are behind the construction of the model. It is a progress of social sciences towards the scientific methods (all things being equal), and it allows to increase the parsimony of urban models.The fourth chapter builds on this quest for parsimony, as it presents an incremental model-building approach to simulate empirical systems of cities. Given the specificity of the system we aim to model, we expect the mechanisms needed to reproduce the observed trajectory to be multiple and interacting in a complex way. Therefore, we have built a framework of hypothesis-testing and implemented modules of mechanisms that we combine and simulate. The combination follows a path of complexification as well as particularisation from any system of cities to a specific case study. The quality of each simulation is evaluated with respect to the populations observed in the corresponding empirical cities. This approach was developed to model the evolution of Soviet and post-Soviet cities from the 1960s on. Its strength is to be transferable at a very low cost to any other national system. A tentative check was performed on Indian cities. We finally show in this chapter that a theoretical-based modular model allows to evaluate and compare the power of different hypotheses to explain urban growth at different periods of time and in different geographical contexts, and therefore suggests a way to account for equifinality in urban models.The fifth chapter corresponds to an innovative way of exploring simulation models, and especially urban models. It considers a parsimonious structure of mechanisms and looks for the diversity of possible outcomes that the model can reach within a reasonable range of parameters. This means that it explores what the trajectory of a system of cities could have been, if we simulate past trends, or what it could be in the future, in terms of two or three properties of the system (like its total population, or the degree of inequality of city sizes). We present the algorithm developed to maximize the diversity of a model’s output, as well as the kind of knowledge it leads to in an empirical context. For instance, we analyze the alternative pasts of the Soviet system of cities (as modelled within different model structures) and the corresponding parameters and their meaning. In particular, we highlight configurations that result in population growth and configurations that result in population shrinkage, configurations that result in hierarchization or in the equalization of city sizes for each of the demographic regimes at two periods of time (Soviet and post-Soviet eras).In the last chapter, we present the platform that brings together and enables all the cutting-edge exploration methods in urban simulation. This integrated, innovative and open toolbox for urban modelling is called OpenMOLE.As an epilogue, we present what could be a world atlas of urban models for global prospective on urban future. We also stress the challenges that hamper its construction so far, especially because of the data challenge that is comparing cities over time and over space. Indeed, each country having (or having not) developed its own way of defining cities and quantifying urban features, there remains a monumental amount of work to collect and harmonize urban data over large period of time, as well as to identify what in each national evolution relates to generic and specific processes. Cumulative modelling could help perform this task, or at least to highlight areas of uncertainties. Our guess is that it will only be achieved by a large collective and interdisciplinary collaboration (between urban and regional specialists, modellers, computer scientists, empirical and theoretical experts, data providers and data analysts) based on open practices (as to data, methods and models).

International audience; The evolution of cities is a major issue because it affects the majority of the world population. It is in cities that solutions must be invented to solve the problems of sustainable development in terms of quality of life, of resource management, of intelligent integration of technological and cultural innovation and of social cohesion, at the local and the global scales. The diversity of cities is such that it might seem difficult to develop a scientific knowledge about them for sustaining policies. However, cities have long been interdependent and organized into systems of cities; they co-evolve through the multiple relationships which connect them into networks for the exchange of materials, investments, people or information. These interdependencies drive and constrain the evolution of each city in the system, according to a complex set of dynamics which exhibit patterns regular enough to help understanding and even predicting certain trends. For anticipating urban future, geographers have since long developed a theoretical framework relying on the observation, not only of the few megacities global stars but of thousands of cities and towns taken in a variety of world regions. These empirical observations were scrutinized through analytic methods inspired from the dynamics of complex systems and data and processes are now integrated into computer simulation models which are able to reconstruct the stylized facts and trends observed. This consolidates an evolutionary theory of urban hierarchies according to which the urban geo-diversity is a necessary condition for continuing the major function of cities and towns that are altogether remarkably efficient socio-spatial adaptors on the long run in the human history.

International audience

International audience; The location of economic activities generates urban specialisations when it is discriminant. The so created interurban differences may persist for a very long time. This is paradoxically explained by the large similarities of economic changes which modify urban acitivities profiles, according to a permanent process of adapting to innovations, within a context of vivid interurban competition.; La localisation de nouvelles activités économiques engendre des spécialisations urbaines lorsqu’elle est sélective. Les différences ainsi créées entre les villes, même anciennes, peuvent persister longtemps. Cela s’explique paradoxalement par une très grande similitude de la plupart des changements économiques qui modifient les profils d’activité des villes, selon un processus permanent d’adaptation aux innovations dans un contexte de forte concurrence interurbaine.

It isn’t to boast about ourselves, but the mental horizons of the world seem to be more and more filled with geography. The environment is increasingly equipped with captors that locate at high speed the prospects for agricultural production as well as the emission of pollutants. Our hitherto indispensable companions in mobility inform us of unimagined quantities of new service providers for our slightest movements. Finding a restaurant in the neighborhood, locating friends who are on the r...

International audience; 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 in different parts of the world and over long time periods, it has been possible to identify stylized facts that characterize their main features and properties. This paper presents data oriented simulations of two kinds of systems: in early settled countries (Europe, 1300-2000) and in countries more recently settled (United States 1650-2000). The model can simulate properly the general dynamics of urban systems, at different scales of observation (general configuration and trajectories of individual cities). The simulations help to identify some dynamic properties that are shared by both systems :1) a general growth trend and spatial expansion (produced through interurban competition which generates emulation towards innovation; this explains the persistency of the hierarchical configuration); 2) a dramatic increase of contrasts in city sizes since the first industrial revolution linked to the increase of communication speed; 3) a differentiation of urban economic functions produced through interactions between cities and innovation cycles, as industrial revolution. The model also put forward the necessary integration of a new urban function in the model, which represents the early emergence of global cities. Yet beyond these similarities in the evolution of all urban systems, when they are fully integrated, the model also measures to what extent the observed peculiarities in their contemporary spatial and functional configuration depend on differences in the early space filling process between the two kinds of systems.