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.
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 20th century.
Figure 1: Urban versus non-urban lands in the Baltimore-Washington DC conurbation. Figure courtesy University of Vermont, Spatial Analysis Laboratory.
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.
- 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.