PhD theses that contributed to GeoDiverCity programme



PhD Clémentine Cottineau

Cottineau C., 2014, The evolution of cities in the post-Soviet Space. Observation and modellings, University Paris I.

Abstract. The Russian and Soviet urbanisation process happened late and fast, compared to other territories. Many new towns and cities were created by the Soviet regime that officially promoted discourses about the socialist function of the city, rational organisation of space and a planned management of the economy. These urban particularities and the multiple demographic and political events of the 20th century have made cities in the post-Soviet space an interesting case and raised question regarding its ruptures and comparability. This dissertation thesis aims to show that the concept of system of cities and generic methods in urban geography (especially models) are useful in the study of urban evolution over the long term in this space, to eventually better understand past trends and predict future ones. We confronted several statistical models with the observed urban dynamics and concluded that the macro-geographical structure of cities in the post-Soviet space was comparable to that of other systems of cities (hierarchy of sizes, spacing, functional differentiation). We also observed specific trajectories related to the size of the territory, natural resources, the recent demographic shrinkage and the effect of particular political decisions. This knowledge about observed evolutions has been included in an incremental approach of agent-based modeling. Starting from theoretical hypotheses about generative mechanisms, we tried to generate generic and specific stylised facts, with a model as parsimonious as possible. The progressive evaluation of increasingly complex models led to the satisfactory simulation of observed urban evolution and highlighted specific trajectories that “resist” modeling.

Key-words. System of cities, Post-Soviet Space, Soviet Union, Generic/Specific, Simulation, Urban evolution, Urban growth.

Link. HAL-SHS.



PhD Clara Schmitt

Schmitt C., 2014, Modeling settlements systems dynamics : from SimpopLocal to SimpopNet, University Paris I.

Abstract. Is urban growth the result of multiple interactions between cities ? Urban evolutionary theory (Pumain, 2000), based on this postulate, analyses urban growth processes. This thesis, undertaken in an inter-disciplinary context, aims to evaluate the validity of the hypothesis by means of computer simulation. Strong regularities of the urban systems dynamics are extracted from the accumulated scientific knowledge and synthetized into ten major stylized facts. Two simulation models, SimpopLocal and SimpopNet, are then built, documented – thanks to a standardized grid – and systematically explored. They each question a specific aspect of the urban evolutionary theory : the nature of the inter-urban interactions for the first model (i.e. competition for innovation) and their support for the second model (i.e. the role of the communication network structure). The evaluation of the two models required the design and the implementation of two original exploration protocols : an automated calibration method and a sensibility analysis protocol (the Exploration Profile algorithm) which individually evaluates the contribution of each implemented mechanism to the simulated behavior. These two forms of exploration systematically confront the simulation results with current scientific knowledge. They indicate that the two models are able to account for key processes of urban systems dynamics, such as their hierarchical organization, and demonstrate for the first time the need for interurban interaction mechanisms in order to simulate urban evolutions that are close to those observed on real urban systems.

Key-words. System of cities, Urban systems, Simpop, SimpopLocal, SimpopNet, Simulation, Urban evolution, Urban growth.

Link. HAL-SHS.


Phd Ignazzi

Ignazzi C. A., 2015, Coevolution in the Brazilian Urban System, University Paris I.

Abstract. This thesis analyzes the urban system in Brazil adopting an advanced database that have been constructed collecting demographic data in order to examine the evolution of the population of all Brazilian agglomerations since the first Brazilian official census carried out in 1872 until 2010.
The largest country of South America has already completed its urban transition during the last century and is characterized by the contrast between a larger number of small towns throughout the immense territory and enormous Metropolitan areas dominating the system of cities.
Despite its geographical and historical peculiarities, this system shares with others in the world the same properties of hierarchical differentiation and urban growth processes (Zipf’s law and Gibrat’s model).
Economic data have been integrated in the database with the aim of testing the validity of scaling laws for Brazil and performing robust statistical analysis in order to explore the functional differentiation of cities, their economic performances and the spatial autocorrelation processes occurring among them.
The most interesting result is characterizing the Brazilian urban hierarchy over the long period and measuring the increasing inequalities in city sizes. Moreover, the parallel support of demographic and economic data is essential to identify the connection between population and economic growth in one of the most urbanized country of the world.

Key-words. System of cities, Urban systems, Urban hierarchy, Zipf, Gibrat, Urban trajectories, Brazil, Functional differentiation, spatial autocorrelation.

Link. Online.



PhD Rey-Coyrehourcq

Rey-Coyrehourcq S., 2015, An integrated platform for building and evaluating model of simulation in geography, University Paris I.

Abstract. Since 1990’s, Agent Based Modelling are commonly used by geographers to study complex systems like cities.
However, very few technical platforms are advanced by searchers to assist in the construction and evaluation of models of simulation. With the help of ERC program GeoDiverCity and the formation of an expert interdisciplinary team, we try to solve these problematic following two objectives. Relying on the support of OpenMOLE platform developed at the Institute of Complex System Paris-Ile-de-France in order to make it simple the distribution of simulation on distributed computing environments, we identify, use or build new tools and methodology to construct and explore model of simulation. To anchor this work in practice, we use this platform to build and explore a new model of simulation: SimpopLocal. This very practical work is accompanied by an historical and epistemological reading of simulation, and the means of simulation in geography. These contextualisation permits us to examine, and perhaps to anticipate, the historical link between the old problematic of “Validation”, very important to consider for knowledge justification, and the building and exploration of models of simulation.

Key-words. Simulation, Agent Based Modelling, Complex systems, Distributed computing environments, Validation.

Link. Online.



PhD Solène Baffi

Baffi S., 2015, Railways and city in territorialization processes in South Africa : from separation to integration?, University Paris I.

Abstract. First railway network in Africa, the South African Railways constitute a privileged marker of the territorial mutations that have been shaping this country for decades. The radicalism of political systems shows through the persistency of segregative schemes of which the railways, as part of the planning toolbox, are one of the elements. The inertia of this infrastructure questions its re-appropriation and insertion into the various planning projects over the long term. This thesis approaches the long-term dynamics of ‘territorialisation’ in South Africa through the prism of railways. This study focuses on the interaction between cities and the railway network, at both the interurban and the intra-urban levels.
In order to understand this interaction, cities’ location and railways diffusion patterns are analysed, with a specific emphasis on the shape of the network. Indeed, through their pattern, railways express the intentions of actors in charge of planning at the national level. By the flows it supports and the mobilities it enhances, it gives us information on the socioeconomic requirements of society and the power relations it contains. Thus, this thesis relies on a qualitative and quantitative approach aiming to outline the structuring effects of the railways in South Africa over the long term.
Its political use by successive segregationist powers explains partly why nowadays railways keep on marking partition in the post-apartheid urban space and in the practices of city dwellers. However, the recent rail renewal observed in the metropolises, Cape Town in particular, might indicate a possible major inflection in the persistency of inherited dynamics. Indeed, the evolution of the rail offer demonstrates a shift towards a co-construction trend between South African society and urban planning unheard of until now.

Key-words. System of cities, Urban system, South Africa, Railways, Territorialisation, Inclusion/exclusion, Intra-urban mobilities.

Link. HAL-SHS.



PhD Olivier Finance

Finance O., 2016, French cities hosting foreign direct investments: from networked companies to localized establishments, University Paris I.

Abstract. Transnational corporations, which are amongst the major players in the contemporary global economy, integrate and exclude territories at various scales, due to their specific location strategies. These inequalities are well known at an international scale, yet the knowledge of this diverse integration is much more limited regarding urban levels, although cities and metropolises are considered as being the major nodes of the globalized networks. France and the OECD countries certainly appear in central positions in the networks that characterize these corporations, but observations made at the urban level remain very partial due to the lack of localized data. This thesis suggests to both approach and localize conventional data about Foreign Direct Investment (FDI) in the French case by mobilizing data about financial links connecting economic units. The detailed breakdown of transnational corporations affiliation networks has been conducted up to the level of the establishments, which are the real individual economic and geographic cells of these transnational networks. An original database about localized inward FDI stocks has been built and explored to appreciate how far foreign transnational corporations integrate the 355 main cities into the French urban system. These data revealed the diverse integration of French cities, between dependence and attractiveness for the investors. The mobilization of scaling laws, which constituted a major analytical tool in this work, allowed us to identify the major factors explaining the diverse integration of French cities into the whole system of cities, reflected both by inequalities of hierarchical and regional order.

Key-words. System of cities, Urban system, France, Scaling laws, Foreign Direct Investment, Transnational firms.

Link. HAL-SHS.


How to estimate the singularity of (post-)Soviet cities?

Revue d'Economie Regionale et Urbaine - n°1 - 2017 New Article, in RERU – Revue d’Économie Régionale et Urbaine.


Cottineau C., 2017, “How to estimate the singularity of (post-)Soviet cities?”, Revue d’Économie Régionale et Urbaine, n°1-2017.

Abstract. Although the urbanisation of the Former Soviet Union is a unique experience, this article questions the possibility of estimating the share of the generic processes of urban growth, spatial location and economic specialisation, the share of the particular processes of urbanisation linked to the size and political organisation of the country, and the share of the singular processes that cannot be explained without a local knowledge of the events which happened in the cities under study. Using several types of models at different scales, we identify the residual as the element that “resists modelling” and illustrates the singular evolutions of the Soviet Union and its cities. To do so, we built a harmonised urban database and fitted hierarchical, spatial and regression models. We conclude that city size inequality increased in a generic manner compared to other systems of cities, that the spatial distribution of cities resemble that of vast countries (especially with the increased reliance on sub-surface resources), and that there exists a set of singular urban trajectories.

Key-words. System of cities, Soviet Union, Singularity, Models, Urban growth, Urban trajectories, Urbanization.

Link. Revue d’Économie Régionale et Urbaine

Urban Dynamics and Simulation Models

Urban Dynamics and Simulation Models | ERC GeoDiverCityNew book, published by Springer International.


Pumain D., Reuillon R. (eds.), 2017, Urban Dynamics and Simulation Models, Springer, 123p.
DOI 10.1007/978-3-319-46497-8

Authors. Chapron P., Chérel G., Cottineau C., Cura R., Leclaire M., Pumain D., Rey-Coyrehourcq S., Reuillon R., Schmitt C., Swerts E.

Abstract. This monograph presents urban simulation methods that help in better understanding urban dynamics. Over historical times, cities have progressively absorbed a larger part of human population and will concentrate three quarters of humankind before the end of the century. This “urban transition” that has totally transformed the way we inhabit the planet is globally understood in its socio-economic rationales but is less frequently questioned as a spatio-temporal process. However, the cities, because they are intrinsically linked in a game of competition for resources and development, self organize in “systems of cities” where their future becomes more and more interdependent. The high frequency and intensity of interactions between cities explain that urban systems all over the world exhibit large similarities in their hierarchical and functional structure and rather regular dynamics. They are complex systems whose emergence, structure and further evolution are widely governed by the multiple kinds of interaction that link the various actors and institutions investing in cities their efforts, capital, knowledge and intelligence. Simulation models that reconstruct this dynamics may help in better understanding it and exploring future plausible evolutions of urban systems. This would provide better insight about how societies can manage the ecological transition at local, regional and global scales. The author has developed a series of instruments that greatly improve the techniques of validation for such models of social sciences that can be submitted to many applications in a variety of geographical situations. Examples are given for several BRICS countries, Europe and United States. The target audience primarily comprises research experts in the field of urban dynamics, but the book may also be beneficial for graduate students.

Key-words. Simulation, Simulation models, Simpop, Systems of Cities, Complexity, Urban systems, Urban systems dynamics, BRICS.

Link. http://www.springer.com/us/book/9783319464954

The Brazilian Urban System: the trajectories of Brazilian cities between general dynamics and specific peculiarities

Brazil-citiesNew Article, in Cybergeo, European Journal of Geography.


Ignazzi C. A., 2015, «The Brazilian Urban System: the trajectories of Brazilian cities between general dynamics and specific peculiarities», Cybergeo : European Journal of Geography, Systems, Modelling, Geostatistics, document 754, DOI:10.4000/cybergeo.27349

Abstract. This article analyzes the dynamic of Brazilian system of cities illustrating the growth of Brazilian population through its own historical peculiarities like internal and international immigration, industrialization, metropolization. Urban hierarchy is revealed by means of the Zipf’s law and Gibrat’s model is used to describe the mechanisms of urban growth. Deviations from this model were explained by studying the specific trajectories of five different classes of cities, on various time scales (from 1872 to 2010 and from 1960 to 2010). These deviations highlight different kinds of factors (political, economic, localization of resources and historical accidents) that shaped the Brazilian system during the last century.

Key-words. Spatial autocorrelation, Urbanization, Brazil, Urban Hierarchy, Trajectories, Zipf’s law, Gibrat’s law, Markov Chains.

Multilevel comparison of large urban systems

New publication, in Cybergeo, European Journal of Geography


Pumain D., Swerts E., Cottineau C., Vacchiani-Marcuzzo C., Ignazzi C.A., Bretagnolle A.,  Delisle F., Cura R., Lizzi L., Baffi S., 2015, « Multilevel comparison of large urban systems », Cybergeo : European Journal of Geography [En ligne], Systèmes, Modélisation, Géostatistiques, document 706, URL : http://cybergeo.revues.org/26730 ; DOI : 10.4000/cybergeo.26730

Abstract. For the first time the systems of cities in seven countries or regions among the largest in the world are made comparable through the building of spatio-temporally standardised statistical databases. We first explain the concept of a generic evolutionary urban unit (“city”) and its necessary adaptations to the information provided by each national statistical system. Second, the hierarchical structure and the urban growth process are compared at macro-scale for the seven countries with reference to Zipf’s and Gibrat’s model: in agreement with an evolutionary theory of urban systems, large similarities shape the hierarchical structure and growth processes in BRICS countries as well as in Europe and United States, despite their positions at different stages in the urban transition that explain some structural peculiarities. Third, the individual trajectories of some10,000 cities are mapped at micro-scale following a cluster analysis of their evolution over the last fifty years. A few common principles extracted from the evolutionary theory of urban systems can explain the diversity of these trajectories, including a specific pattern in their geographical repartition in the Chinese case. We conclude that the observations at macro-level when summarized as stylised facts can help in designing simulation models of urban systems whereas the urban trajectories identified at mico-level are consistent enough for constituting the basis of plausible future population projections.

Key-words. Urban systems, Zipf, Gibrat, Cities trajectories, BRICS

GeoDiverCity at AAG Annual Meeting 2014 in Tampa, Florida

Various contributions of GeoDiverCity team are scheduled for the Annual Meeting of the Association of American Geographers in Tampa, Florida :

Tuesday, 4/8/2014

> Session : 1654 European Research Council – Top European grants for brilliant minds from across the world, from 4:40 PM – 6:20 PM in Grand Salon C, Marriott, Second Floor. Organizer : Katja Meinke.

17:15-17:30    Denise Pumain, “ERC from an Advanced Grantee’s perspective.”

Wednesday, 4/9/2014

> Session : 2268 Urban systems and scaling laws: Functional diversity and urban economic trajectories, from 10:00 AM – 11:40 AM in Meeting Room 1, Marriott, Second Floor. Organizer : Céline Vacchiani-Marcuzzo.

10:00-10:20    Elfie Swerts, Céline Vacchiani-Marcuzzo, Fabien Paulus, “Scaling laws as a tool for characterising the functional evolution in urban systems”

10:20-10:40    Olivier Finance, “Transnational firms in the French system of cities and scaling laws”

> Session : 2239 Geosimulation Models 1: Methodological Advances, from 10:00 AM – 11:40 AM in Room 39, TCC, Fourth Floor. Organizers : Paul Torrens, Suzana Dragicevic, Andrew Crooks.

11:20-11:40    Mathieu Leclaire, Romain Reuillon, “Simpuzzle/Janet tools or how to build a step by step modular ABM ?”

> Session : 2539 Geosimulation Models 3 : Applications – Macro, from 2:40 PM – 4:20 PM in Room 39, TCC, Fourth Floor. Organizers : Paul Torrens, Suzana Dragicevic, Andrew Crooks.

14:00-14:20    Clémentine Cottineau, Paul Chapron, “Evaluation & Calibration for the comparison of ABMs of cities’ trajectories”

16:00-16:20  Denise Pumain, Clara Schmitt, Sébastien Rey-Coyrehourcq, Romain Reuillon, “Building and exploring an agent-based model with OpenMOLE”

Cities and Transport relations in South Africa over the long-term

The aim of my study 1 is to understand the role of South African cities in the transport flux and networks, and how cities and transport are interacting, from colonization in the 17thuntil nowadays. If cities and transport interactions are a particularly interesting approach to understand the metropolisation process and the urban system building, the South African context makes it even more relevant. Indeed, South Africa is a young country and national transport networks such as the railway network, have been built while the urban system was formed.

Co-evolution of urban system and railway network in South Africa

The arrival of European settlers in 1652 to the Cape of Good Hope marked the beginning of South African modern history, in particular by initiating the urbanization process. Until then, no city, strictly speaking, existed yet (Coquery-Vidrovitch). The implementation of a settlement engaged the constitution of an urban system well connected with Europe, but not very well between cities (Vacchiani-Marcuzzo).

The discovery of the goldfields and diamond mines in the 1860’s overturned that system. In the heart of the mining region, Johannesburg faced a fast growth to become the biggest metropolis in the country. The emergence of this new centre deeply modified the urban structure by switching the country’s centre of gravity from the coast to the Witwatersrand. Indeed, the British Empire decided to experiment inner-city railways in Cape Town and Durban in the 1860’s. But given the mining revolution, the decision to extend it to the entire country was quickly made in order to dispatch the mining extractions from the Witwatersrand plateau to the shoreline before having them exported to Europe. Hence, in a bit less than 100 years, a 20 000 km railway network has been built.

The implementation of such a network whereas the urban system was formed enables us to talk about a co-evolution of urban system and transport network in South Africa. Citie’s growth has largely been influenced by their position on the railway network. Large cities benefitted from a better accessibility, which reinforced their centrality while small towns had to deal with the simplification of urban hierarchy. As in many other countries, we can notice the strong interaction between cities and transport and its effect on the process of cities selection, particularly reinforced  by the railway network in the South African example.

I started my research by focusing on the railway network given it seemed easier to start with an historical approach at the larger scale. To observe and study this co-evolution we decided to cross two databases created in Geographie-Cités. The first one, built in the research program Harmonie-Cités, gathers data about the evolution of South African cities (of more than 5 000 inhabitants) over almost a century. To create this database, South African censuses have been used. The second one, made up in the frame of Geodivercity research program, contains data about the railway network’s development in South Africa and has been built thanks to the SARH archives. By crossing these databases, we created maps over 60 years which show the concomitant evolution of the urban system and railway network.

Now, I intend to deepen my analysis and enlarge my focus to the implementation of transport in metropolitan areas on one hand, and the position of South Africa in global networks on the other.

Solène Baffi

Notes:

  1. PhD project of Solène Baffi, under the supervision of Anne Bretagnolle, Olivier Ninot, Denise Pumain and Celine Vacchiani-Marcuzzo (founded by ERC GeoDiverCity)

The global hierarchy of port cities in 1890 based on steamer vessel traffic

The enormous concentration of traffic upon a few large cities confirms the paramount importance of the Atlantic area (London, Liverpool, Cardiff, and New York) as well as of specific poles such as Hamburg and Buenos Aires, the latter being at the time a growing rival of European capitals. Other cities stand out less by their traffic than by their important share of steamer traffic, among which Antwerp, Bombay, Baltimore, and New Orleans. Asia is the region outside Europe hosting the largest number of cities specialized in steamer traffic.
For more information on data and further analyses (in French):
http://www.cnrs.fr/inshs/recherche/reseau-maritime-mondial.htm

César Ducruet

Flows of steamer vessels among world regions in 1890

Based on the circulation of 4,772 merchant vessels on the period January-April 1890 (Source: Lloyd’s Weekly Shipping Index), the map reveals a trading system highly polarized by Europe and the United States – the main commercial centres at the time. The proportion of most modern vessels (steamers) in total traffic (including sailing vessels propelled by wind) concentrate on the most beneficial and frequent routes (Europe-USA) but also highlight the deployment of this recent innovation towards Asia and Africa in a context of reinforced colonial interests following the opening of the Suez canal (1869).

César Ducruet