Image Processing Reference
In-Depth Information
Urban Structure and Urban Growth: An Overview
of Theories and Methodologies
Cities emerge and evolve from the coalescence and symbiotic interaction of infra-
structures, people and economic activities. These interactions are systematic, gener-
ally in that they are related to development in the global
economy, and more specifically in that they manifest building
and transport technologies. But these interactions are also
sensitive to local context, in that settlements are individually
resilient to constraints in their evolutionary path. Given
advances in technology, and the sheer scale and pace of con-
temporary urban growth, the most rapid changes in urban
form, pattern and structure, are taking place where historical
roots are weakest - as in the recent suburbs of long estab-
lished Western cities, or in the new cities of developing coun-
tries. A city like London would never have been able to
develop its contemporary form, skyline, and density of activity
were it not for technological innovations such as its under-
ground transport network and its role in global financial mar-
kets. Yet there are local and institutional factors such as the role of “green belt
planning policy,” peculiar to the UK that has prevented the kind of sprawl charac-
teristic of North American cities taking hold throughout the functional region.
Traditional urban theories investigate how cities develop and grow through these
kinds of interactions, and in macro terms are based on advantages that co-location
(i.e., the physical location where urban and economic activities are in close spatial
proximity to one another) can offer to economies and societies. Agglomeration
economies, defined by those economic production systems that benefit from co-
location, have been identified as key forces at work in the growth of cities at any
time and in every place. However, over the last half century our traditional under-
standing that the only outcomes of these forces should be an accelerating concen-
tration of population, infrastructures and jobs has been challenged by the evidence
of de-concentration, first in the United States and now in Europe. The migration of
agricultural populations into the city which has been a centuries old factor in rural
depopulation and the dominant force in creating urban agglomerations is now giving
way to a reverse migration into the countryside, at least in many western cities, as
suburbanization and sprawl become the modus operandi of urban growth.
Of course, the inertia in the skeletal structure of the built form of the city in its
buildings and streets are important principally because they accommodate the loci
of activities of “urban” populations. There is nearly a century of interest in understand-
ing the socio-spatial differentiation of urban populations, that can be traced back to
the 1920s in the work of Park, Burgess and the Chicago School of urban ecologists,
if not before in the writings of Max Weber and his nineteenth century contemporaries.
Here again, urban research has focused upon the general as well as the specific.
The classic ringed socio-economic structure of 1920s Chicago, for example, was
urban theories
investigate how
cities develop
and grow
interactions of
people and
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