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Adrian Guillermo Aguilar and Josefina Hernández Lozano Institute of Geography, UNAM IGU Urban Commission Meeting, 14-20 August 2011, Canterbury U.K. Metropolitan Transformation and Polycentric Structure in Mexico City . Identification of Urban Subcenters , 1989-2009.
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Adrian Guillermo Aguilar and Josefina Hernández Lozano Institute of Geography, UNAM IGU Urban Commission Meeting, 14-20 August 2011, Canterbury U.K. Metropolitan TransformationandPolycentricStructure in MexicoCity. Identificationof Urban Subcenters, 1989-2009
Main Questions: • To what extent the metropolitan space of Mexico City presents a policentric structure regarding the spatial distribution of employment? • What are the main changes on spatial patterns of urban subcenters in the period 1989-2009? • What are the differences in the spatial dynamic by economic sectors? • What areas are winning or losing jobsand what factors seem to explain that situation?
I. Policentrism and Metropolitan Transformation The spatial dynamic indicates a movement of activities from the city center to the periphery that tends to form a “concentrated deconcentration” pattern. Urban subcenters function as nodes articulating space with a relevant employment density and concentration. The urban form of the new clusters change the landscape: corridors, compact subcenters, dispersed activities areas, high rise buldings, etc.
Agglomeration economies play a fundamenal role. The benefits of being close to other activities creates a cluster of bussiness activities that favour each other. • A main difficulty is to define a threshold that indicates a significative number of jobs to constitute a subcenter. • The traditional CBD normally is still very important. This is valid particularly for activities that need “face to face” contact: financial, commercial, public administration.
II. Urban Expansion in Mexico City. Recent Trends • A depopulation of the city center with a dominant tertiarization. A revitalization around: new housing, corporate offices, tourism, commercial activities, etc. • A deindustrialization of urban economy with manufacturing spreading towards peripheral locations. • Peripheral expansion with high population growth rates, but low and very dispersed employment concentrations.
III. Identification of Urban Subcenters • The Economic Census was used in the period 1989-2009; the spatial unit used was the basic geostatistical area (AGEB); data were processed for economic sectors and subsectors. • To identify urban subcenters a double threshold method was selected. The AGEBs classified as urban subcenters had to comply to the following criteria: - A concentration of employment superior to the city mean, plus a standard deviation.
The Central Business District • In the period this area concentrated the highest number of subcenters and employment in the city (45%). • The presence of services is outstanding in this zone. Employment on services predominates in 66% of the subcenters. • Commercial activities show a slow growth; and manufacturing continues to move away from the central city.
The First Ring • The first ring had a constant increase of employment, with 41% of all the employment of the identified subcenters. • This ring has the most important concentration of manufacturing employment in the city. • A marked dispersion trend of services employment to the south of the ring is relevant: Periferico Sur, Insurgentes Ave. Santa Fe.
The Second Ring • Employment in the second ring also has an increasing trend, but only contains 10% of all jobs in the city. • Manufacturing jobs predominate in number, and subcenters show stability in the north of the city. • Service and commercial activities show a similar number but a slow concentration.
Conclusions • In the last 25 years there has been a gradual formation of urban subcenters with a “concentrated deconcentration” in compact subcenters and corridors. • However this structure is highly restricted: it is relevant for the city center, 1st and 2nd rings. But in the 3rd and 4th rings the presence of these subcenters is almost unexistant. • The central city is still the largest concentration of employment (46%) despite the loss of resident population.
The central city shows a proliferation of subcenters leading to spatial widening of the concentration of activities with larger subcenters. • The city centrality of employment has experienced a displacement towards the western and southern zones, with larger areas in each subcenter. • The lack of important peripheral economic concentrations shows a lack of balance and equity in the distribution of jobs for the poorer neighborhoods to the northern and eastern areas.