Eric Gielen

Clustering cities through urban metrics analysis

Abstract This paper describes a process for measuring and characterizing urban morphological zones. These urban zones are delineated for the entire area of Spain, independently of administrative boundaries and excluding demographic data, using a high resolution land-use dataset. Given the rich information available on land cover and subsequently assigned population data, it is possible to calculate a set of urban spatial metrics to classify these urban zones into homogenous morphological groups. Four types of urban agglomerations are identified in Spain by working with these urban metrics and applying a final cluster analysis. Although these groups have a general complex monocentric typology, each has its own specific characteristics. Finally, a picture of patterns and trends of urbanization for the main urban agglomerations in Spain is provided, offering some perspectives on the urban sprawl phenomenon.

An urban sprawl index based on multivariate and Bayesian factor analysis with application at the municipality level in Valencia

Urban sprawl is now a common and threatening phenomenon in Europe, severely affecting environmental and economic sustainability. An analytical characterization and measurement of urban sprawl are required to gain a better understanding of the phenomenon and to propose the possible solutions. Traditional factor analysis techniques, especially Principal Component Analysis and Factor Analysis, have been commonly used. In this paper, we additionally test Independent Component Analysis with the aim to obtain a multidimensional characterization of the sprawl phenomenon. We also use Bayesian Factor Analysis to obtain a single (unidimensional) measuring index of sprawl, which also allows us to obtain the uncertainty of the inferred index, in contrast to traditional approaches. All these techniques have been applied to study the phenomenon of urban sprawl at the municipality level in Valencia, Spain using a wide set of variables related to the characteristics and patterns of urban land use.

MULTIDIMENSIONAL CHARACTERIZATION OF THE REGIONAL URBAN MODEL AND THE URBAN SPRAWL IN VALENCIA

The big urban development produced in Spain about last 30 years has produced a paradigm shift in the regional urban model. The traditionally compact city has become a scattered city. This phenomenon is usual in the American model but is relatively new in Spain and in the European context. Many of the contemporary cities present an urban sprawl model. In this situation, the city is not only constituted by its historical nucleus and its extension, but also includes discontinuous urban land. Therefore, new analysis tools are needed. This paper shows a part of PhD research and studies the characterization of the pattern of urban occupation from a morphological perspective. The application of multivariate statistical techniques allows to reduce an initial set of 12 variables in five independent dimensions: density, fragmentation, distance, complexity and extension. It is shown that the urban sprawl is a multidimensional phenomenon. The research conclude that urban sprawl is an urban model of occupation of the territory, characterized by low density settlements spread over large areas, fragmented in several urban units, distant between them and defining a complex structure. The research has been carried out in the Valencian Community at the municipal level. As a result, the five dimensions of the urban model have been calculated to all municipalities. This has allowed to identify processes of urban dispersion in the coastal areas and the metropolitan areas of the most important cities.