Transcript
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1. CONCEPTUALLY AND STATISTICALLY
DEFINING URBAN AMERICA
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Urbanization, The Dominant Trend Around The World
For first time, more than half of world’s population is living in urban places
Based on State of World Population 2007 report from United Nations
By 2030, urbanization rate will be 60%
Compare with rate of world urbanization rate of 30% in 1950
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Urbanization: More Developed vs. Less Developed Countries
Between 2007 and 2030, the urban share will rise from 75% to 81% in more developed countries
In less developed countries, urban share will rise from 44% to 56%
WORLD'S LARGEST POPULATED CITIES ARE CONCENTRATED IN ASIA
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DEFINING URBAN AMERICA:CONCEPTUAL AND STATISTICAL
INTERPRETATIONS
Need to distinguish between urbanization and urban growth.
Important difference exists between these two processes.
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Urbanization: a process whereby a society is transformed from an essentially rural to a predominantly urban one.
Two comparable indicators of urbanization:
• The proportion of the total population of an area
concentrated in urban settlement.
• The proportion of a place’s total area that is dedicated to
urban (as opposed to rural) land uses.
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URBANIZATION (two indicators)
The process has a beginning and an end
Urban Population X 100
Total Population
Urban Land Area X 100
Total Land Area
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URBAN POPULATION GROWTH:
In contrast, the growth of cities has no inherent limits.
P2 - P1
________________ P1
OR
X 100
[(P2/P1) - 1] x 100
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Thus, cities can grow without any increase in urbanization if:
The rural population grew at an equal or greater rate.
If place is 100% urbanized, but continues to grow because
births exceed deaths or foreign immigration is larger than any exodus of nationals.
Ratio of urban to rural land areas remains the same or
declines.
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IS IT POSSIBLE TO BE IN FAVOR OF URBAN GROWTH BUT NOT TO BE IN FAVOR OF
URBANIZATION?
OR VICE VERSA?
MORE THAN AN ACADEMIC QUESTION!!
RATHER, A PHILOSOPHICAL POSITION ON HOW
OUR SETTLEMENTS SHOULD LOOK AND FUNCTION.
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URBAN SETTLEMENT PHILOSOPHY
PRO-URBANIZATION (second definition)
ANTI-URBANIZATION (second definition)
PRO-URBAN GROWTH
ANTI-URBAN GROWTH
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URBAN SETTLEMENT PHILOSOPHY
PRO-URBANIZATION (second definition)
ANTI-URBANIZATION (second definition)
PRO-URBAN GROWTH
Urban population growing and increasing share of settlement area in urban land uses. The current reality.
ANTI-URBAN GROWTH
No or limited urban population growth and share of urban land uses shrinking (or constant) relative to rural land area. Urban land may be reclaimed for "natural" uses.
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URBAN SETTLEMENT PHILOSOPHY
PRO-URBANIZATION (second definition)
ANTI-URBANIZATION (second definition)
PRO-URBAN GROWTH
Urban population growing and increasing share of settlement area in urban land uses. The current reality.
Urban population growing BUT growth restricted to limited land area. Strategy: Maintain urban land use boundary to concentrate urban population growth. Must result in some locations with higher land-use densities.
ANTI-URBAN GROWTH
No or limited urban population growth, but increasing share of settlement area in urban land uses. Typical of parts of upstate New York state. Sprawl without urban growth. Results in lower population densities.
No or limited urban population growth and share of urban land uses shrinking (or constant) relative to rural land area. Urban land may be reclaimed for "natural" uses.
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FUNDAMENTAL LESSON
Clearly, both urban growth and urbanization measures depend on the particular way in which settlements are defined as urban.
In practice, U.S. Census (Department of Commerce)
typically used as basis to define urban status.
GEOGRAPHIC AREAS USED
BY U.S. CENSUS BUREAU
TO DEFINE URBAN AND
RURAL AREAS IN THE
UNITED STATES17
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Counties The primary legal division of every state except Alaska
(Boroughs and municipalities) and Louisiana (Parishes). Fairly stable units; therefore good for statistical/research purposes.
3,142 counties in the United States. 67 in Florida.
U. S. Census treats parish as equivalent to county for data
summary purposes. Familiar Louisiana example.
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Census Tracts
Small, relatively permanent geographic subdivisions of a county.
Provide a nationwide set of geographic units that have
stable boundaries.
65,000 census tracts across the United States.
Used to measure internal diversity of a metropolitan area.
A reasonably compact, continuous land area, all parts of
which are internally accessible by road.
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Population Thresholds for Census Tracts
Area(s) Optimum Minimum Maximum
United States, Puerto Rico, Virgin Islands of the U.S.
4,000 1,500 8,000
43 census tracts in Alachua county
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Alachua County Divided into Census Tracts
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Census Block Group
Block groups are geographic subdivisions of census tracts. Provide a geographic summary unit for census block data.
A block group must comprise a reasonably compact and contiguous cluster of census blocks.
Each census tract contains a minimum of one block group and may have a maximum of nine block groups.
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Population Thresholds for Block Groups
Area(s) Optimum
Minimum Maximum
United States, Puerto Rico, Virgin Islands of the U.S.
1,500 600 3,000
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Census Block Census tracts/block groups are subdivided into standard city
blocks
Smallest unit of data tabulation.
More fine-grained internal diversity.
Blocks are well-defined, usually rectangular pieces of land bounded by 4 streets, or other visible features.
May be irregular in shape.
Blocks do not cross boundaries of census tracts or counties.
Average about 100 people.
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IN FLORIDA (2010)
4,245 census tracts
11,442 block groups
484,481 census blocks
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Population Density
Persons per square mile is the average number of inhabitants per square mile of land area.
Divide the total number of residents by the number
of square miles of land area in the specified geographic area.
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URBAN AND RURAL CLASSIFICATIONS
Urban area Used by the U.S. Census Bureau since year 2000 to refer collectively
to Urbanized areas (UA) and Urban clusters (UC). Urbanized Area (UA) Geographic entity consists of a densely settled area with a census
population of at least 50,000. A UA generally consists of a geographic CORE of block groups or blocks that have a population density of at least 1,000 people per square mile, and adjacent block groups and blocks with at least 500 people per square mile.
Urban Cluster (UC) Geographic entity consists of densely settled area with a census
population of 2,500 to 49,999. A UC generally consists of a geographic CORE of block groups or blocks with a population density of at least 1,000 people per square mile and adjacent densely settled block groups and blocks with at least 500 people per square mile.
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Urban Area Title Criteria For those urban areas that contain an incorporated place
with at least 2,500 people.Self-governing unit with legally defined boundaries
established under state law.Legally constituted governmental functions—such as,
providing various types of services.Separate identity that controls much of its own
development (e.g., ability to tax and collect revenues) The urban area title includes the name of the incorporated
place with the most population within the urban area. As many as two additional incorporated place names may
be part of the urban area title. “Urban areas” do not cross over state boundaries.
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RURAL The Census Bureau's classification of "rural" consists of all
territory, population, and housing units located outside of UAs and UCs.
Census tracts, counties, metropolitan areas, and the territory
outside metropolitan areas, often are "split" between urban and rural territory.
URBAN-RURAL DISTRIBUTION In the year 2009, 68% of Americans lived in 452 Urbanized
Areas and 11% lived in 3,158 Urban Clusters.
Thus, 79% of Americans lived in urban America.
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METROPOLITAN AND MICROPOLITAN AREAS More widely used for research and policy. The U.S. Office of Management and Budget establishes the
standards by which to define Metropolitan Statistical Areas and Micropolitan Statistical Areas.
Areas with a relatively large population nucleus and adjacent
communities that have a high degree of integration with that nucleus.
All statistical areas are made up of one or more counties. Judging whether adjacent counties are included usually
based on measures of job commuting ties. Metros and Micros can cross over state boundaries.
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Metropolitan Statistical Area (metro area)
Metropolitan Statistical Area (metro area) • Consists of a Census Bureau-defined of at least one
urbanized area that has a population of at least 50,000.
• The metro area comprises the central county or counties
containing this CORE population, plus adjacent outlying counties that have a high degree of social and economic integration with the central county as measured through commuting ties.
Remember: urbanized areas must meet both size and density requirements.
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How to Define Central Counties
Every metropolitan or micropolitan area contains at least
one central county.
Some areas also contain one or more outlying counties.
The central county or counties:
Contain all or a substantial portion of an urbanized area
or urban cluster.
These counties, in turn, are used to measure commuting
to and from counties that potentially qualify as outlying
counties.
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How to Define Outlying Counties
• A county qualifies as an outlying county of a MSA if it meets the following commuting requirements:
at least 25 percent of the employed residents of the county (e.g., Gilchrist) work in the central county or counties (e.g., Alachua) of the MSA
or
at least 25 percent of the employment in the county (workers in Gilchrist) is accounted for by workers who reside in the central county or counties (e.g., Alachua) of the MSA.
A county may appear in only one MSA.
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Micropolitan Statistical Area (micro area)
Consists of at least one urban cluster that has a CORE population of at least 10,000, but less than 50,000.
The micro area comprises the central county or counties containing this CORE population, plus adjacent outlying counties having a high degree of social and economic integration with the central county as measured through commuting.
As of 2013, there are there are 381 Metropolitan Statistical areas and 536 Micropolitan Statistical areas in the United States.
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Core Based Statistical Areas (CBSAs)
Umbrella term: Includes two settlement categories—Metropolitan Statistical Areas and Micropolitan Statistical Areas. Thus, CBSAs encompass all settlement types in U.S. except places with population and territory outside of metro and micro areas. Thus, CBSAs exclude the most rural or noncore areas.
METROPOLITAN STATISTICAL AREAS NONMETROPOLITAN AREAS or Rural America
Micropolitan Statistical AreasNoncore Areas
U. S. Population by Core Based Statistical Area Status, 2010
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Why larger share of U.S. populationconsidered urban when using MSAs than Urbanized Areas?
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Metropolitan Division
A subdivision unit of a CBSA (usually MSAs). Must contain a core of at least 2.5 million population. A metro division consists of one or more counties that represent an employment center or centers plus adjacent counties associated through commuting ties.
In Florida, for example, the Miami-Fort Lauderdale-West Palm Beach, FL. MSA is divided up into three Metropolitan Divisions (one county each).
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Principal Cities (Central Cities) and Metropolitan and Micropolitan Statistical Area Titles
The largest city in each metropolitan or micropolitan statistical area is designated a "principal city.“
Additional cities qualify if specified requirements are met concerning population size and employment.
The title of each Metropolitan or Micropolitan Statistical Area consists of the names of up to three of its principal cities and the name of each state into which the metropolitan or micropolitan statistical area extends.
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Suburbs (area outside of central cities/principal cities) of metropolitan area
Area outside of principal/central cities, but within the boundaries of metropolitan area (counties) will often be referred to as the suburbs of the metropolitan area.
Issue: Need for metropolitan areas to include whole
counties and implications for defining suburban and rural populations.
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Florida’s Metropolitan Statistical Areas
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22 MSA’s(2013)
Florida’s Nonmetropolitan Statistical Areas
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2013
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CHALLENGES OF MEASURING URBAN GROWTH AND URBANIZATION
Population Size
1990 2000 Growth Rate (%)
Gainesville MSA
204,111 217,955 6.8
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CHALLENGES OF MEASURING URBAN GROWTH AND URBANIZATION
Population Size
1990 2000 Growth Rate (%)
1990-2000 Variable Boundaries
Alachua 181,596 217,955
Bradford 22,515
Total 204,111 217,955 6.8%
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CHALLENGES OF MEASURING URBAN GROWTH AND URBANIZATION
Population Size
1990 2000 Growth Rate (%)
Year 1990 Constant Boundaries
Alachua 181,596 217,955
Bradford 22,515 26,088
Total 204,111 244,043 19.6
Year 2000 Constant Boundaries
Alachua 181,596 217,955
Bradford
Total 181,596 217,955 20.0
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U.S. Census Regions
WEST MIDWEST NORTHEAST SOUTH
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CONCEPTUAL INTERPRETATIONS OF URBAN AMERICA Central Business District (Downtown)—CBD (part of
central/principal city) An area of high land valuation characterized by a high
concentration of retail businesses, service businesses, offices, theatres, and hotels and by a high traffic flow.
Generally considered the essence of an urban place. Inner City (part of central/principal city) Surrounding downtown is the oldest built-up and relatively
higher population-density urban area of metropolitan area consisting of both residential and nonresidential land uses.
BOSTON, MASS.
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SEATTLE, WASHINGTON
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SAN FRANCISCO, CA.
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CONCEPTUAL INTERPRETATIONS OF URBAN AMERICA
Inner Ring/First-Tier Suburbs Earliest built residential suburbs of the metropolitan area
Outer Ring Suburbs Later built residential suburbs of the metropolitan area
Exurban Areas Rural territory within defined metropolitan areas, typically
beyond the built-up suburbs, not in central county(ies) but within long-distance commuting range of urban employment opportunities
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Megalopolis (Gottman, 1961)
A loose amalgamation of several metropolitan areas into a single massive region. e.g., Northeastern United States (New Jersey, New York, Philadelphia, Atlantic City), San Diego to San Francisco; Chicago-Pittsburgh corridor.
Not only refers to a continuous mass of urban spaces but also the places linked together by virtue of telecommunications, airline routes, and other types of flows.
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Newer Terminology: Megapolitan Areas (Metropolitan Institute at Virginia Tech)
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SHOULD WE DEFINE URBAN BASED ON:SITE OR SITUATION INDICATORS?
SITE: ecological criteria such as size, density, characteristics of the
population, housing, or land uses, natural landscapes, voting patterns, other settlement features
absolute locational as opposed to relative locational features
has to do with form or attribute features as opposed to
functional relationships with outside areas
has to do with the phenomena in an area but not their
linkages with other places
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SITUATION:
a place's linkages with other places
extent of a place's geographic isolation
a place's connections with other places
the influences of one place on another
concerned with flows, market areas, spheres of influence,
geographic ties, transportation patterns of people and communication flows of information
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Daily Urban System (Brian Berry, 1970s) (example of urban "situation")
Was looking for an alternative approach to measure the extent that the U.S. population lived in urban areas.
Not happy with measuring “urban” by population size or
density. Constructed urban regions based on the level of commuting
by workers to central city core counties of metropolitan areas. Defining urban this way greatly increases the extent of the
population AND territory that falls within the sphere of an urban center.
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SPRAWL
Pattern of land use in an urban area that exhibits low levels
of some combination of eight distinct dimensions: density,
continuity, concentration, compactness, centrality,
nuclearity, diversity, and proximity.
We’ll focus on only six key dimensions of sprawl.
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Chicago EXAMPLE:
Between 1970 and 1990 the population of the Chicago metropolitan area increased by only 4 percent but the amount of land in the region used for urban purposes grew by 35 percent.
Altogether 454 square miles, twice the size of the city
of Chicago, were converted from agricultural to urban uses over that 20-year span.
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Baltimore EXAMPLE:
Between 1960 and 1990 the population of the Baltimore metropolitan area increased by 33 percent but the amount of land in the region used for urban purposes grew five fold—by 170 percent.
If Maryland continued at its current rate of development over the next 25 years, it would lose over 500,000 acres of forests and farmland—the size of Baltimore County and Baltimore City combined.
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1. Density: the average number of residential units per square mile of developable land in an urban area.
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2. Continuity: the degree to which developable land has been developed at urban densities in an unbroken fashion.
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3. Concentration: the degree to which development is located in relatively few square miles of the total urban area.
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4. Compactness: the degree to which development has been "clustered" to minimize the amount of land in each square mile of developable land occupied by residential or nonresidential uses.
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5. Centrality: the degree to which residential and/or nonresidential development is located close to the central business district of an urban area.
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6. Nuclearity: the extent to which an urban area is characterized by a mononuclear (as contrasted with a polynuclear) pattern of development
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NOTE: MOST SPRAWLING URBANIZED AREA IS ATLANTA; LEAST SPRAWLING URBANIZED AREA
IS NEW YORK
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