Megaregion, Urban

Definition:  

An urban megaregion is a sub-continental scaled assemblage of dense urban settlements, edge cities, suburbs, exurbs, agricultural or pastoral lands, and wild lands.  Often linear in form, megaregions can span hundreds of miles, and are connected by Interstate highways or motorways, main rail lines, and short to medium distance air routes.  In opposition to the earlier concept and manifestation of regional urbanization identified as a megalopolis, in urban megaregions the urban cores are relatively indistinct and decentralized, urban development has multiple nodes, and the boundaries between urban, suburban, and exurban land covers are spatially complex and fuzzy.  Commuting may be in several directions, including movement between edge cities and suburban transport nodes, between different suburban nodes, and between suburbs and old central cities.  Furthermore, in the megaregions of the United States, the economic engine has shifted from industrial production to economies based on service, innovation, and consumption.

Examples:

The megaregion has essentially replaced both the metropolis and the megalopolis as the predominant form of urbanization in many parts of the world.  Baltimore is part of the US Northeastern Urban Megaregion, which runs from Richmond, Virginia, to Portland, Maine (Fig 6). 

  

Figure 6. The Northeastern Urban Megaregion of the United States.  Diameter of circles is proportional to individual metropolitan area population.  From: Regional Plan Association, America 2050.

 

There are ten urban megaregions in the United States, and they also exist in Europe and Asia, for example (Fig. 7). 

Figure 7. The urban megaregions in the United States, projected to 2050.  From Regional Plan Association, America 2050.

Why Important:

The urban megaregion concept emphasizes the spatial extent, diffuse boundaries, and complex governance of urban areas today.  Although it owes much to the megalopolis concept, the megaregion idea indicates that the concentration of power and wealth that characterized the core, industrial (e.g. Baltimore) or financial (e.g. New York) centers has dispersed.  

  

Figure 8.  The complexity of  the Northeastern Urban Megaregion as a spatial mosaic.  Densityof red color indicates the proportion of impervious land cover.  Natural ecoregions are shown as the background map.  University of Vermont, Spatial Analysis Lab.

Urban regions are composed of mosaics of intermingled, yet contrasting land covers and land uses (Fig. 8), so that interactions among those patches are more intense, and perhaps more conflicted than when urban areas were more clearly differentiated metropolises with large rural areas between them.  The megaregion is a new form of urban organization, and its implications for social-ecological research and action are yet to be settled.

For more information:

§  Gottmann, J. 1961. Megalopolis: the urbanized northeastern seaboard of the United States. The Twentieth Century Fund, New York.

§  Lang, R. E. and D. Dhavale. 2005. Beyond megalopolis: exploring America's new "megalopolitan" geography. Metropolitan Institute at Virginia Tech, Blacksburg, VA.

§  Regional Plan Association. 2007. Northeast megaregion 2050: a common future. Regional Plan Association, New York.

§  Vicino, T. J., B. Hanlon, and J. R. Short. 2007. Megalopolis 50 years on: the transformation of a city region. International Journal of Urban and Regional Research 31:344-367.

Urban

Definition: Urban has two definitions.  
1) The broad definition refers to any built up area, including central cities and suburbs, where buildings, roads, and energy and material delivery and waste processing infrastructure are present and the livelihoods of the residents depend on economic consumption or production rather than management of natural resources.  
2) The narrow, specific definition of urban refers to the dense portions of settlements, including business centers, apartment blocks, row homes and small lot residential neighborhoods.  The narrow sense urban contrasts with less dense residential subdivisions and suburbs.

The US Census Bureau (2010) has specific definitions it uses:  

“For the 2010 Census…To qualify as an urban area, the territory identified according to criteria must encompass at least 2,500 people, at least 1,500 of which reside outside institutional group quarters.  The Census Bureau identifies two types of urban areas:

• Urbanized Areas (UAs) of 50,000 or more people;
• Urban Clusters (UCs) of at least 2,500 and less than 50,000 people.

“Rural” encompasses all population, housing, and territory not included within an urban area.”

Examples: The Baltimore, Maryland, metropolitan area, consisting of parts or all of six jurisdictions – Baltimore City, Baltimore, Harford, Carroll, Howard and Ann Arundel Counties, is an example of the broad sense of urban (Figure 1).  An example of the narrow sense of urban is a dense, old residential neighborhood (Figure 2), or an established subdivision closely associated with a dense business or commercial center (Figure 3).  Figure: 1) A satellite image classified as urban or non urban from UVM SAL. 2) A Baltimore row house neighborhood.  3) The Roland Park development from the early 20^th century.

Figure 1: Urban versus non-urban lands in the Baltimore-Washington DC conurbation.  Figure courtesy University of Vermont, Spatial Analysis Laboratory.

Figure 2. A dense rowhouse neighborhood in Baltimore, MD, which would be classified as urban in the strict sense.

Figure 3. Zoning map of the Roland Park neighborhood in north Baltimore City.  Developed in 1891, the project included a trolley line in the boulevard of Roland Avenue, and a small commercial strip on Roland at Upland Road.  Like other early American streetcar suburbs, portions of Roland Park were designed by Frederick Law Olmsted.  Curving streets, dense tree canopy, and capacious single family houses on large lots characterize the core of this neighborhood.

Why important:  Defining “urban” for specific research projects is a requirement for effective comparison and communication.  There is no single definition of urban, and even various nations and states use different quantitative criteria for discriminating urban.  However, it is important to say at least what sense of urban – narrow or broad – is being used in a particular study or discussion and also to specify any qualitative or quantitative criteria used.

For more information: 

• US Census (2010) http://www.census.gov/geo/www/ua/2010urbanruralclass.html

• McIntyre, N. E., K. Knowles-Yanez, and D. Hope. 2000. Urban ecology as an interdisciplinary field: differences in the use of "urban" between the social and natural sciences. Urban Ecosystems 4:5-24.