World map showing percent of
population living in an urban environment.
An
urban area is characterized by higher
population density and vast human features in comparison to areas
surrounding it. Urban areas may be
cities,
towns or
conurbations, but the term is not commonly
extended to
rural settlements such as
villages and
hamlets.
Urban areas are created and further developed by the process of
urbanization. Measuring the extent of
an urban area helps in analyzing
population density and
urban sprawl, and in determining urban and
rural populations (Cubillas 2007).
Unlike an urban area, a
metropolitan
area includes not only the urban area, but also
satellite cities plus intervening
rural land that is socio-economically connected to the
urban core city, typically by
employment
ties through
commuting, with the urban
core city being the primary labor market. In fact, urbanized areas
agglomerate and grow as the core population/economic activity
center within a larger metropolitan area or envelope.
Metropolitan areas tend to be defined using counties or county
sized political units as building blocks. Counties tend to be
stable political boundaries; economists prefer to work with
economic and social statistics based on metropolitan areas.
Urbanized areas are a more relevant statistic for determining per
capita land usage and densities (Dumlao & Felizmenio
1976).
Definitions
They vary somewhat amongst different nations.
European countries define urbanized areas on the
basis of urban-type
land use, not allowing
any gaps of typically more than 200 meters, and use
satellite photos instead of census blocks
to determine the boundaries of the urban area. In less developed
countries, in addition to land use and density requirements, a
requirement that a large majority of the population, typically 75%,
is not engaged in agriculture and/or fishing is sometimes
used.
Australia
In Australia, urban areas are referred to as "urban centres" and
are defined as population clusters of 1000 or more people, with a
density of 200 or more persons per square kilometre.
Canada
In
Canada
, an urban area is an area that has more than 400
people per square kilometre and has more than 1,000 people.
If two or more urban areas are within two kilometres of each other,
they are merged into a single urban area. The boundaries of an
urban area are not influenced by municipal or even provincial
boundaries.
China
In China, an urban area is an urban district, city and town with a
population density higher than 1,500 persons per square kilometre.
As for urban districts with a population density lower than 1,500
persons per square kilometre, only the population that lives in
streets, town sites, and adjacent villages is counted as urban
population.
France
In
France
, an urban area is a zone
(aire urbaine) encompassing an
area of built-up growth (called an "urban unit" (unité urbaine) - close in definition
to the North American urban area) and its
commuter belt (couronne
périurbaine). Although the official
INSEE translation of
aire
urbaine is "urban area", most North Americans would find
the same as being similar in definition to their
metropolitan area.
Japan
In
Japan
urbanized areas are defined as contiguous areas of
densely inhabited districts (DIDs) using census enumeration districts as units with a density
requirement of .
New Zealand
Statistics New Zealand
defines
New Zealand urban
areas for statistical purposes as a settlement with a
population of a thousand people or more.
Norway
Statistics Norway defines urban
areas ("tettsteder") similarly to the other Nordic countries.
Unlike in Denmark and Sweden, the distance between each building
has to be of less than 50 meters, although exceptions are made due
to parks, industrial areas, rivers, and similar. Groups of houses
less than 400 metres from the main body of an urban area are
included in the urban area.
Poland
In
Poland
, official "urban" population figures simply refer
to those localities which have the status of towns
(miasta). The "rural" population is that of all
areas outside the boundaries of these towns. This distinction may
give a misleading impression in some cases, since some localities
with only village status may have acquired larger and denser
populations than many smaller towns.
Sweden
Urban areas in Sweden
(
tätorter) are statistically defined localities, totally
independent of the administrative subdivision of the country. There
are 1,940 such localities in Sweden, with a population ranging from
200 to 1,252,000 inhabitants.
England and Wales
The
United
Kingdom
's Office
of National Statistics produced census results from urban areas
since 1951, since 1981 based upon the extent of irreversible urban
development indicated on Ordnance Survey
maps. The definition is an extent of at
least 20 hectares and at least 1,500 census residents. Separate
areas are linked if less than 200 meters apart. Included are
transportation features.
KS01 Usual resident population: Census 2001, Key
Statistics for urban areas
For the OS definition of an Urban Area, see the notes tab on the
Excel version.
United States
In the
United
States
there are two categories of urban area. The
term
urbanized area denotes an urban area of 50,000 or
more people. Urban areas under 50,000 people are called
urban
clusters. Urbanized areas were first delineated in the United
States in the 1950 census, while urban clusters were added in the
2000 census. There are 1,371
urban areas and urban
clusters with more than 10,000 people.
The U.S. Census Bureau defines an urban area as: "Core census block
groups or
blocks that have a population
density of at least 1,000 people per square mile (386 per square
kilometer) and surrounding census blocks that have an overall
density of at least 500 people per square mile (193 per square
kilometer)."
The concept of Urbanized Areas as defined by the U.S. Census Bureau
are often used as a more accurate gauge of the size of a city,
since in different cities and states the lines between city borders
and the urbanized area of that city are often not the same.
For
example, the city of Greenville, South Carolina
has a city population under 60,000 but an urbanized
area over 300,000, while Greensboro, North Carolina
has a city population over 200,000 but an urbanized
area population of around 270,000 — meaning that Greenville is
actually "larger" for some intents and purposes, but not for
others, such as taxation, local elections, etc.
The
largest urban area in the United States is that of New York City
, with its city proper
population exceeding 8 million and its metropolitan area population
almost 19 million. The next four largest urban areas in the U.S.
are those of Los
Angeles
, Chicago
, Miami
and Philadelphia
. About 70 percent of the population of the
United States lives within the boundaries of urbanized area (210
out of 300 million). Combined, these areas occupy about 2 percent
of the United States. The majority of urbanized area residents are
suburbanites; core central city residents make up about 30 percent
of the urbanized area population (about 60 out of 210
million).
See also
References
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