Archives de catégorie : Project 3

PhD theses that contributed to GeoDiverCity programme

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phd-swerts

Swerts E., 2013, The Indian and Chinese Systems of Cities , University Paris I.

Abstract. This thesis compares the urban systems in China and India using dedicated data bases that have been constructed using comparable and harmonized principles, describing the evolution of the population of all urban agglomerations above 10 000 inhabitants, every ten years from the beginning of 20th century for India and 1964 for China. Both very large countries of ancient urbanization are characterized by many small towns and have developed gigantic metropolises during the last decades. Despite their geo-historical specific features, these two systems share with others in the world the same properties of hierarchical differentiation and urban growth processes (Zipf’s law and Gibrat’s model), at country scale as well as for regional subsystems. A regional diversity is linked to former processes of unequal concentration of urban development. The most interesting result is identifying for the first time a reverse trend in the evolution of the Chinese urban hierarchy compared to other countries in the world among which India: despite the very rapid recent urban growth, the inequalities in city sizes are decreasing. This may in part depend of the under-registration of migrant urban populations. It also reveals the power of the political control on China’s urban processes that also appears in the magnitude of spatial concentration of manufacturing cities due to the implantation of Special economic Zones. Comparing the trajectories of Indian and Chinese cities may well improve the prospect of global urbanization that is crucial for the world and the planet.

Key-words. System of cities, Urban hierarchy, Zipf, Gibrat, Urban trajectories, China, India.

Link. HAL-SHS.


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.

Urban Dynamics and Simulation Models

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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 rising stars of urban growth in China

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The unbridled and three-dimensional development of Chinese cities is spectacular. It has been initially concentrated in the coastal area, since the economic reorientation of the Chinese economy and its productive system has at first been based on export-oriented manufacturing. The coastal cities, more open to the World than the central and western ones, have provided leverages for this development. Their driving role has been strongly reinforced by the creation of the Special Economic Zones (SEZ) since the 1980’s, firstly implanted in this area. However, the recent evolution of the Chinese economy and society could shift the scheme of an economic development based on coastal cities, and the current highest growth could be very different from the cities growth economic potential. A typology of the demographic trajectories of Chinese cities from 1982 to 2010 (Swerts & Liao, 2016) including all cities above 10 000 inhabitants according to an harmonized definition (Swerts, 2013) highlighted that cities whose demographic weight increases in the Chinese system are not only located in the East coast, but also in Central and Western China (figure 1). In terms of size categories, the most dynamic Chinese cities were both million plus cities and small cities (from 10,000 to 100,000 inhabitants).

The fastest growing small towns are mostly located at short distances of about 200 km around the largest metropolises. The increasing weight of some small towns and the stability of some large cities, as well as the current development of the Central and Western cities, could partly result from the strong emergence of an internal market, the increasing role of the tertiary sector in the Chinese economy and the more frequent creation of SEZ in Central and Western part of the country since the 1990’s. On the other hand, while the development of Chinese cities is highly linked to the evolution of the administrative system (Ma, 2005; Lin, 2005), the Chinese government has decreed successive decentralization reforms. These reforms could have fostered the economic development of the prefecture level cities and of the district level cities, the smallest ones.

Fig. 1. Trajectories of the Chinese cities from 1982 to 2010 (ChinaCities database, Swerts, 2013)Trajectories Chinese Cities 1982-2010

These changes could also generate long-term transformations of the functional organization of the Chinese urban system: including the expansion of the tertiary sector and the diversification of the cities’ economy and a strongest development of industrial activities out of the Eastern coast. The cities of the central and western part of China are mostly cities whose economy is diversified, some of them with an overrepresentation of manufacturing activities, and others that are mostly cities of less than 100,000 inhabitants, with an overrepresentation of tertiary activities (figure 2). Nowadays, the economic profile of the most dynamic cities is very diversified. The strongest potential for economic growth could thus shift from the Eastern coast to all over the country, although a strong growth still remains a characteristic of industrial coastal cities, in particular those in the Yangzi river delta, the Pearl River Delta and the area around Beijing.

Fig. 2. Functional specialization of Chinese Cities in 2000 (ChinaCities databases, Swerts, 2013)Functional spcecialisation Chinese Cities

International newspapers recently pointed out nine cities that reflect the strong potential of development of western and central cities, including a few non-metro cities. These cities are Chongqing (7.3 millions of inhabitants), Chengdu (6.4 million), Zhengzhou (4.1 million), Guiyang (2.4 million), Huainan (1.4 million), Xiangyyang (1.1 million), Suqian (274,594), Hengyang (165,824) and Zhuozhou (152,709). They are all cases illustrating the spatial deconcentration of the Chinese economic development (Fig. 2 & http://geodivercity.parisgeo.cnrs.fr/blog/2013/10/the-first-image-of-functional-specializations-among-chinese-urban-agglomerations/), as all are located in the Central and Western part of China (Fig 3).

Fig.3. Chinese rising stars?Chinese Rising Stars

These cities are very different in size, from some 150,000 inhabitants to more than 7 millions. This diversity is representative of the dynamics primed in China since the 1980’s. Some of these cities are province capitals, as Chengdu and Zhengzhou – and the Province level city Chongqing. The others cities are located between 50 and 250 km from their Province capitals. Zhuozhou excepted, all of them are prefecture level cities. In average, the Chinese cities annual growth rate between 1982 and 2010 is 3.3 % while the annual growth rate of these cities vary from 2% (Guiyang) to more than 5% (Chongqing or Suqian).

Tabl.1Chinese Rising Stars Table

These nine cities all have a diversified economy with an overrepresentation of the innovative tertiary sector, Huaibei and Hengyang excepted. In Huaibei, 40% of the employed population (source ChinaCities) is engaged in manufacturing activities, whereas 22% of the employed population of Hengyang is engaged in manufacturing, and 23% in building industry. This last city’s economy may be not so sustainable. From an investor point of view, urban growth rates over 4 or 5% or even 10% are attractive, but it is well known that rapid urban growth always occur with high fluctuations in space and time. Knowledge about deliberate national policies may help to secure predictions but more detailed information about the evolution of economic profiles on comparative basis also may enlighten further perspectives.

Elfie Swerts

How large are Chinese and Indian cities?

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Reliable figures of cities’ population sizes are a great and useful by-product of comparative geographical analysis. We have identified which are now the major urban concentrations in the largest two countries of the world. Table 1 below provides the list of the population in top 30 Indian cities in 1981 and 2011 and top 30 Chinese cities in 1982 and 2010. In this table the last column on the right side enables comparing our results with figures that are given in official censuses of each country.

Table 1. Population of the 30 largest cities in India 1981 and 2011 and in China in 1982 and 2010Population 30 largest cities India ChinaSource: E. Swerts, 2013, for India : Indiacities database and Indian census; for ChinaCities database and Chinese Census

 

Towards mega-cities and megalopolises of a new kind

The multisecular Chinese and Indian urban development that intensified since the 1980’s fascinates the observers, largely because it has produced supersized cities, as Shanghai, Delhi and Beijing counting each around 20 million inhabitants. These cities are and will remain on the list of the 10 largest Urban Agglomerations in the World. They do not yet reach the size of formerly developed urban concentrations around Tokyo (38 millions in 2015 according to the United Nations, 43 according to PopulationData.net) or even New York (19 millions in 2015 according to the United Nations, 23 according to PopulationData.net ) but due to their growth rate it is very likely that during the next decades, gigantic conurbations will organize around them: in China three megalopolises are already forming between Beijing and Tianjin, from Shanghai to Nanjing and between Guangzhou and Hong-Kong (including Shenzhen, Dongguan and Zhuhai) (figure 1). In India, the same could occur around Delhi and Kolkata, and from Mumbai to Pune (figure 2). In Kerala the deviations between our database and the census in tentative sizing the agglomerations of Kochi or Thiruvananthapuram reflects the very peculiar expansion of urbanization in that region, which tend to mix very dense urban and rural areas in a way slightly different from Indonesian or Chinese “desakota” (McGee, 1991).

Figure 1. The 30 Largest Cities in China in 201030 largest cities ChinaSource: Chinacities database, E. Swerts (2013)

 

Figure 2. The 30 Largest Cities in India in 201130 largest cities IndiaSource: Indiacities database, E. Swerts (2013)

 

Safer data for research as well

Gigantic efforts have been made by many authors for establishing safer figures on the size of urban agglomerations in a comparable way and avoiding big mistakes as in papers electing Chongqing as the largest “city” in the world. Chongqing was supposed to reach from 32 to 34 million of inhabitants [ref] Links : http://www.lefigaro.fr/international/2016/04/06/01003-20160406ARTFIG00304-34-millions-d-habitants-chongqing-folle-megapole-chinoise.php, http://www.straitstimes.com/asia/east-asia/chongqing-picked-for-3rd-govt-to-govt-project, http://www.lejdd.fr/International/Asie/Actualite/Chongqing-34-millions-d-habitants-93658 and http://www.lesechos.fr/week-end/voyages/voyages/021666536748-aux-sources-de-lharmonie-1199824.php [/ref] because of a confusion in translating the Chinese word for “municipality” that may indeed denote a “province” (in that case covering 82 300 km2, approximately the size of Austria!) whereas the population of the agglomeration, although already large enough, oscillate between 7 or 10 millions according to different sources.

Of course for comparing cities and assessing dynamic urbanization processes building data base where the size of cities is comparable in time and space is absolutely necessary and this step of the work was duly accomplished in GeoDiverCity’s work, for Europe (Rozenblat, 1992; Guerois et al. 2009), Former Soviet Union (Cottineau, 2014), India (Swerts, 2013), China (Swerts, 2013), United States (Bretagnolle et al., 2015), Brazil (Ignazzi, 2015) and South Africa (Baffi, 2016, Vacchiani-Marcuzzo, 2005). All these data bases will be made freely accessible in due time, including detailed information about their methodology and metadata. The methodology employed by Elfie Swerts for building the data bases on India and China is made explicit in the annex in the full post.

Elfie Swerts

Continuer la lecture →

GeoDiverCity at AAG Annual Meeting 2014 in Tampa, Florida

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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 »

Complex Systems and Geography

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GeoDiverCity Team was active at presenting their work to a diverse and large audience at the inauguration of the Complex Systems Institute in Paris.

Here are some documents we presented :

> A selection of visual results in geographical modeling

[gview file= »http://geodivercity.parisgeo.cnrs.fr/blog/wp-content/uploads/2014/03/GeoModelingok1.pdf »]

Paul Chapron, Clémentine Cottineau, Robin Cura, César Ducruet, Julie Fen-Chong, Sébastien Haule, Marion Le Texier, Nora Marei and Clara Schmitt

Picture Refs : 1. C. Cottineau, 2. D. Holten & J. W. Jarke, 3. R. Cura, 4.5. C. Ducruet, 6. M. Le Texier, 7. C. Cottineau, 8. P. Chapron, 9.10. C. Schmitt

> Netlogo models of systems of cities

  • SimpopNet

Clara Schmitt

 

  • MARIUS : Modeling of Agglomerations of Imperial Russia and the Soviet Union

Clémentine Cottineau and Paul Chapron

 

> A poster about a method to conceive, build and evaluate models at the intersection of generic systems of cities and the specific case of post-Soviet cities

Clémentine Cottineau, Paul Chapron, Denise Pumain and Romain Reuillon

 

> Accessing the European Grid computing power

Mathieu Leclaire and Romain Reuillon

 

The first image of functional specializations among Chinese urban agglomerations

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Until now the industrial landscape of urban China was described only for the 647 “cities” as they were officially named (shi). Thanks to the ChinaCities data base built by Elfie Swerts using standardized delineation of urban agglomerations (that are thus comparable with other urban entities similarly defined in other regions in the world) it is now possible to provide a general view of employment profiles[ref] Population figures are computed in the Chinacities data base; data about employment in 14 activity sectors are extracted from Chinese census at district level (Source: China data center, University of Michigan). The 14 sectors are following: Mining and Quarrying –  Production and Supply of Electric Power – Gas and Water – Geological Prospecting and Water Conservancy – Manufacturing –  Construction –  Transport, Storage, Postal and Telecommunication Services –  Wholesale & Retail Trade and Catering Services –  Finance and Insurance –  Real Estate –  Social Services – Health Care, Sports and Social Welfare –  Education, Culture and Arts, Radio, Film, Television – Scientific Research and Polytechnic Services – Governments Agencies, Party agencies and Social Organizations. [/ref]peculiarities within the whole Chinese urban system.

As in other countries in every part of the world, the major difference among cities’ roles in Chinese economy is between “central places” ensuring the provision of services to the local and surrounding population together with the politico-administrative territorial control, and the manufacturing centers producing material goods.

Central places (in blue on the map) are disseminated according to a rather regular pattern whose density follows roughly the density of population. Among them, the smallest towns (in dark blue color) are relatively more specialized in services with a low share of their employment in other sectors, whereas the largest (in light blue) also include other types of activity, namely manufacturing, construction and real estate that accompany their bursting growth.

On the contrary, cities that are specialized in manufacturing activities with an average proportion of almost two thirds of employment (in red) – a very high ratio for large cities that is today typical of developing countries- are remarkably concentrated along the Eastern coastline, from the Pearl River delta to the Yangtze estuary. Their spatial distribution is mainly explained by the location of the Special Economic Zones since 1978 that generated higher rates of urban growth (6 % per year between 1982 and 2000) compared to the other agglomerations of the urban system (4.5%). A few exceptions are located in more central parts of the country, along the north-south axis and in Ex Manchuria or in the Western desert areas. Most of them are very specialized mining towns with at least 40% of their employment in extractive activities or probably other mono-activity manufacturing centers (Yanbianchaoxianzu and Helong in Jilin province, Qitaihe in Heilongjiang, Tiefa in Liaoning)

This spatial pattern is not surprising, knowing the almost absolute dedication of Chinese manufacturing production to exported goods, but as the cities in question are very large for most of them (1 to 5 millions of inhabitants), this extreme spatial concentration raises interrogation about their further evolution when the internal Chinese market will develop. Which infrastructure and logistic reorganization will allow the re-equilibration of urban development and functional portfolio of Chinese cities in the next coming decades?

Elfie Swerts

Singularities of urban systems in China and India

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We show for the first time comparable and exhaustive maps of cities for the largest two countries of the world[ref] Urban data bases have been built by Elfie Swerts from a variety of statistical and geographical sources according to a unified concept of urban agglomeration (continuously built up area). [/ref]. Around year 2000 there represent the precise location of about 11 000 cities above 10 000 inhabitants in China and 7000 in India, regrouping respectively 690 and 380 million of urban citizens (figure 1 and 2).

Two subcontinents of megacities and small towns

A major singularity common to both urban systems when compared to the rest of the world is the combination of huge metropolises with a high density of numerous smaller towns. Each country has at least three megacities above 10 million inhabitants (Shanghai, Beijing, Guanzhou, Delhi, Mumbai, Kolkata) and Shanghai and Delhi are even each above 20 million. No doubt that in the next decades more very large urban centers will emerge, many of the largest cities of the world will be found in Asia and even a handful of gigantic conurbations called “megalopolis”.

But the distinctive feature of these urban systems is their dense underlying pattern of small towns with population between 10 000 and 50 000 inhabitants, of which there are almost 9 000 in China and 5 400 in India. One third of the urban population of each country lives in these relatively small settlements (whereas the proportion is only 25% in Europe and 5% in the United States of America). These small settlements are disseminated in every region, according to a rather more regular spatial pattern in India compared to the asymmetry between sporadic Western and denser Eastern urbanization in China (due to environmental and historical factors).

Figure 1 Population sizes of urban agglomerations in China (year 2000)

Source : Swerts Chinacities, urban agglomerations above 10 000 inhabitants

Figure 2 Population sizes of urban agglomerations in India (year 2001)

Source : Swerts, Indiapolis and IndiaCensus, urban agglomerations above 10 000 inhabitants

Two different types of urban hierarchies

Even if both countries share with all other urban systems a strong differentiation of city sizes according to a Zipf’s distribution, China appears as an exception in the world. Although the share of urban population is higher in China (urbanization rate = 60% against 40% only in India) the index which measures the level of inequalities of city sizes in the system (that is the slope of the adjusted rank-size curve) is only 0.8 in China (against 0.9 in India) (figure 3). Moreover, while the general trend in India, in conformity with observations in other parts of the world is an increase of these urban size differences during the historical urbanization process, the slope has been decreasing during the last forty years in China. That can certainly be explained by the strength of urban and spatial planning policies in this country – even if an uncertainty remains about the identification of urban population because of the hukou system. It is also a demonstration that an evolution toward more and more hierarchy in urban systems is not as inescapable as it may appear from uncontrolled urban dynamics in most world countries.

Figure 3 Rank-size distributions of cities in China and India around 2000

Sources : China : Swerts, ChinaCities (2000), India : Swerts, Indiapolis (2001)

Elfie Swerts


Evolution and urban modeling: a complexity perspective on the Brazilian city system

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The project performed in this thesis, aiming at the knowledge of the Brazilian system of cities, sets out to demonstrate, within an historical and legal frame, the peculiarities of the history of urbanization in Brazil, a large and populous developing country that is widely considered to have completed an early urban transition.

Undertaking a research on this topics means, primarily, to handle with a problem of an apparent dearth of literature; even if is possible to find many works on Brazilian urbanization, above all in Portuguese language, only a few of these treats urbanization under the aegis of complex systems, as an adaptation process to changes arising from massive urbanization and from insertion in a global, hierarchized network of cities, in which, each metropolitan area is compelled to adapt its internal structure in response to demographic, economic and technical changes. Brazilian main centers will be considered as nodes of a hierarchized structure extending their influence over other agglomerations and territories.

A complexity perspective can provide a general appropriate context within which to understand the behavior of socio-economic systems, notably urban cities systems; computer based models will be associated to a geographical conception in order to analyze urban systems starting with geographical and historical data and trying to foresee their future dynamics through modeling.

By the means of an analysis of both geographical conception and computer-based conception of cities, we will try to set up a model that simulates the peculiarities and so the dynamics of cities and this will be explicitly done using the software Netlogo in order to realize a simulation of a cities system in Brazil. The testing done with our model will be also used to simulate the possible effects of climate changes on the future evolution of urbanization.

Cosmo Antonio Ignazzi