18 research outputs found
Data Linkage
This guide provides an overview of data linkage, analyses the main advantages, and summarizes the challenges quantitative researchers and data practitioners face when working
with multiple data sources. Moreover, this document aims to provide examples of the developments of data linkage in Switzerland as well as inform practitioners about key steps
when linking data
The future of India's urbanization
International audienceIn 2050, urban India will be home to fourteen per cent of the world's urban population. In less than thirty years, half of India's population will have to cope with urban life and there will be tremendous transformation of landscape, economic structure and social life. In order to forecast India's urban future, we assumed that secular and contemporary growth trajectories of all individual urban agglomerations are key drivers of future urbanization trends. We demonstrate that India's city-system conforms to the distributed growth model and that its hierarchical distribution is evolving regularly. India's plurisecular city-system fits well with the canonical model that describes universally the system dynamics. It shares common characteristics with several mature urban structures around the world. We show also that the location of the town has little influence on its growth trajectory. Nevertheless, individual trajectories can be classified, either by the secular trend of towns (1901-2011) or on the basis of the more recent genesis of the contemporary urban agglomerations landscape (1961-2011). These classifications are structured over time and space according to subsystems and regional specificities
Multilevel comparison of large urban systems
For the first time the systems of cities in seven countries or regions among
the largest in the world (China, India, Brazil, Europe, the Former Soviet Union
(FSU), the United States and South Africa) are made comparable through the
building of spatio-temporal 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 some 10,000 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 micro-level are consistent enough for
constituting the basis of plausible future population projections.Comment: 14 pages, 9 figures; Pumain, Denise, et al. "Multilevel comparison of
large urban systems." Cybergeo: European Journal of Geography (2015
Urban networks in China and India
Lâanalyse de la structure des systĂšmes de villes en Inde et en Chine et de leur Ă©volution au long du XXe siĂšcle pour lâInde et depuis les annĂ©es 1960 pour la Chine a Ă©tĂ© menĂ©e Ă partir de bases de donnĂ©es comparables et harmonisĂ©es, construites spĂ©cifiquement dans le cadre de cette thĂšse et dĂ©crivant lâensemble des agglomĂ©rations de plus de 10000 habitants. Les deux pays, trĂšs anciennement mais encore peu urbanisĂ©s, conservent de trĂšs nombreuses petites villes tout en ayant dĂ©veloppĂ© au cours des derniĂšres dĂ©cennies de gigantesques mĂ©tropoles de plusieurs dizaines de millions dâhabitants. En dĂ©pit de leurs singularitĂ©s gĂ©o-historiques, ces deux systĂšmes prĂ©sentent les mĂȘmes rĂ©gularitĂ©s fortes que les systĂšmes dĂ©jĂ connus (loi de Zipf et modĂšle de Gibrat), et ce quelle que soit lâĂ©chelle dâobservation : un mĂȘme processus de croissance distribuĂ©e traduit lâunitĂ© des hiĂ©rarchies urbaines indienne et chinois Ă©tant dans leur ensemble quâau sein de leurs sous-systĂšmes rĂ©gionaux. Nous mettons cependant en Ă©vidence une diversitĂ© rĂ©gionale rĂ©vĂ©lĂ©e par lâhĂ©tĂ©rogĂ©nĂ©itĂ© dâune rĂ©gion Ă lâautre des degrĂ©s dâinĂ©galitĂ© de la taille des villes et de leurs rythmes de croissance. La primautĂ© de certaines capitales rĂ©gionales rĂ©sulte en gĂ©nĂ©ral de concentrations politico-administratives antĂ©rieures Ă notre pĂ©riode dâobservation. Le rĂ©sultat le plus marquant est que le systĂšme de villes chinois se singularise des autres systĂšmes, y compris indien, par une diminution dans le temps de son degrĂ© de hiĂ©rarchisation, ce qui nâa jamais Ă©tĂ© observĂ© auparavant. Le contrĂŽle politique des mĂ©canismes dâĂ©volution des villes aurait alors inflĂ©chi non pas la totalitĂ© du processus dâurbanisation mais le sens de son Ă©volution. (Il est possible que le sous-enregistrement des populations migrantes explique pour partie ce rĂ©sultat). Lâinfluence de ce contrĂŽle se traduit aussi au niveau de lâorganisation fonctionnelle du systĂšme de villes, lâĂ©tablissement des ZES ayant conduit Ă la concentration saisissante des villes industrielles dans des espaces restreints, autour des Deltas de la riviĂšre des Perles et du Yangzi, ainsi que dans une moindre mesure dans le Bohai Rim. Les trajectoires comparĂ©es des villes indiennes et chinoises permettent dâenrichir la prospective de lâurbanisation qui reprĂ©sente dâĂ©normes enjeux pour le monde et la planĂšte.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 10000 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 (Zipfâs law and Gibratâs model), at country scal aswell 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 amongwhich 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 Chinaâs 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
Les SystĂšmes de Villes en Inde et en Chine
This thesis compares the urban systems in China and India using dedicated databases that have been constructed using comparable and harmonized principles,describing the evolution of the population of all urban agglomerations above10 000 inhabitants, every ten years from the beginning of 20th century for Indiaand 1964 for China. Both very large countries of ancient urbanization arecharacterized by many small towns and have developed gigantic metropolisesduring the last decades.Despite their geo-historical specific features, these two systems share with othersin the world the same properties of hierarchical differentiation and urban growthprocesses (Zipfâs law and Gibratâs model), at country scale as well as for regionalsubsystems. A regional diversity is linked to former processes of unequalconcentration of urban development.The most interesting result is identifying for the first time a reverse trend in theevolution of the Chinese urban hierarchy compared to other countries in the worldamong which India: despite the very rapid recent urban growth, the inequalities incity sizes are decreasing. This may in part depend of the under-registration ofmigrant urban populations. It also reveals the power of the political control onChinaâs urban processes that also appears in the magnitude of spatialconcentration of manufacturing cities due to the implantation of Special economicZones.Comparing the trajectories of Indian and Chinese cities may well improve theprospect of global urbanization that is crucial for the world and the planet.Lâanalyse de la structure des systĂšmes de villes en Inde et en Chine et de leurĂ©volution au long du XXe siĂšcle pour lâInde et depuis les annĂ©es 1960 pour laChine a Ă©tĂ© menĂ©e Ă partir de bases de donnĂ©es comparables et harmonisĂ©es,construites spĂ©cifiquement dans le cadre de cette thĂšse et dĂ©crivant lâensemble desagglomĂ©rations de plus de 10 000 habitants. Les deux pays, trĂšs anciennementmais encore peu urbanisĂ©s, conservent de trĂšs nombreuses petites villes tout enayant dĂ©veloppĂ© au cours des derniĂšres dĂ©cennies de gigantesques mĂ©tropoles deplusieurs dizaines de millions dâhabitants.En dĂ©pit de leurs singularitĂ©s gĂ©o-historiques, ces deux systĂšmes prĂ©sentent lesmĂȘmes rĂ©gularitĂ©s fortes que les systĂšmes dĂ©jĂ connus (loi de Zipf et modĂšle deGibrat), et ce quelle que soit lâĂ©chelle dâobservation : un mĂȘme processus decroissance distribuĂ©e traduit lâunitĂ© des hiĂ©rarchies urbaines indienne et chinoisetant dans leur ensemble quâau sein de leurs sous-systĂšmes rĂ©gionaux. Nousmettons cependant en Ă©vidence une diversitĂ© rĂ©gionale rĂ©vĂ©lĂ©e par lâhĂ©tĂ©rogĂ©nĂ©itĂ©dâune rĂ©gion Ă lâautre des degrĂ©s dâinĂ©galitĂ© de la taille des villes et de leursrythmes de croissance. La primautĂ© de certaines capitales rĂ©gionales rĂ©sulte engĂ©nĂ©ral de concentrations politico-administratives antĂ©rieures Ă notre pĂ©riodedâobservation.Le rĂ©sultat le plus marquant est que le systĂšme de villes chinois se singularise desautres systĂšmes, y compris indien, par une diminution dans le temps de son degrĂ©de hiĂ©rarchisation, ce qui nâa jamais Ă©tĂ© observĂ© auparavant. Le contrĂŽle politiquedes mĂ©canismes dâĂ©volution des villes aurait alors inflĂ©chi non pas la totalitĂ© duprocessus dâurbanisation mais le sens de son Ă©volution. (Il est possible que lesous-enregistrement des populations migrantes explique pour partie ce rĂ©sultat).Lâinfluence de ce contrĂŽle se traduit aussi au niveau de lâorganisationfonctionnelle du systĂšme de villes, lâĂ©tablissement des ZES ayant conduit Ă laconcentration saisissante des villes industrielles dans des espaces restreints, autourdes Deltas de la riviĂšre des Perles et du Yangzi, ainsi que dans une moindremesure dans le Bohai Rim.Les trajectoires comparĂ©es des villes indiennes et chinoises permettent dâenrichirla prospective de lâurbanisation qui reprĂ©sente dâĂ©normes enjeux pour le monde etla planĂšte
A data base on Chinese urbanization: ChinaCities
In China, the measurement of the citiesâ population is confusing. Indeed, the administrative boundaries do not delineate a âstrictly urbanâ unit, but include a territory composed both of urban and rural territories which are under the jurisdiction of a main city. This article describes the construction method and the content of a new harmonized database of the Chinese citiesâ population, the ChinaCities database
Peut-on estimer la population des villes chinoises à partir de leur surface bùtie ?
Chinese cities are growing so rapidly that we have to implement appropriate methods to measure their size and analyze their evolution. As administrative subdivisions are variable as well as the available sources about urban population, we suggest an estimation based on built-up areas. Landsat satellite images are analyzed for extracting continuously built-up areas. Estimations of the built-up surfaces are provided for about fifty urban agglomerations from 1980 to 2000. They are then compared to population figures given by different data bases in a variety of international sources. Nonlinear relationships between surfaces and population are computed. They demonstrate that our estimations of surfaces are consistent and reliable. However, the evolutions of surfaces as well as population figures are too variable to be reliable. Consequently, the same method cannot be used and has to be supplemented with other sources