Editing Metropolitan area (section)

==Definition==
[[File:Hoja-especial-50-Madrid y su entorno-2012.jpg|thumb|upright=1.5|A metropolitan area usually includes a main city and a series of smaller satellite cities as can be seen in this map of [[Madrid]]'s metropolitan area (click on the map to enlarge it).]]
A metropolitan area combines an [[urban agglomeration]] with the contiguous built-up areas, which are not necessarily urban in character but are closely bound to the center by employment or other commerce. These outlying zones are sometimes known as a commuter belt and may extend well beyond the urban zone to other political entities. For example, [[East Hampton, New York]], on [[Long Island]] is considered part of the [[New York metropolitan area]].

In 2020, the [[European Commission]], the [[Food and Agriculture Organization]], the [[United Nations Human Settlements Programme]], the [[International Labour Organization]], the [[OECD]], and the [[World Bank]] have agreed on a common methodological framework for delimitation of urban and rural areas, which contains a definition of metropolitan areas called the [[Functional urban area]].<ref>{{cite book |author=European Union/FAO/UN-Habitat/OECD/The World Bank |date=2021 |doi=10.2785/706535 |isbn=978-92-76-20306-3 |language=en |location=Luxembourg |page=51 |publisher=Publications Office of the European Union |title=Applying the Degree of Urbanisation — A methodological manual to define cities, towns and rural areas for international comparisons — 2021 edition |url=https://ec.europa.eu/eurostat/documents/3859598/15348338/KS-02-20-499-EN-N.pdf/0d412b58-046f-750b-0f48-7134f1a3a4c2?t=1669111363941 |doi-access=free }}<!-- auto-translated from Polish by Module:CS1 translator --></ref> It is defined as a city and its commuting zone, which is a contiguous area of spatial units that have at least 15% of their employed residents working in the city.<ref>{{cite book |author=European Union/FAO/UN-Habitat/OECD/The World Bank |date=2021 |doi=10.2785/706535 |isbn=978-92-76-20306-3 |language=en |location=Luxembourg |page=52 |publisher=Publications Office of the European Union |title=Applying the Degree of Urbanisation — A methodological manual to define cities, towns and rural areas for international comparisons — 2021 edition |url=https://ec.europa.eu/eurostat/documents/3859598/15348338/KS-02-20-499-EN-N.pdf/0d412b58-046f-750b-0f48-7134f1a3a4c2?t=1669111363941 |doi-access=free }}<!-- auto-translated from Polish by Module:CS1 translator --></ref>

In practice, the parameters of metropolitan areas, in both official and unofficial usage, are not consistent. Sometimes they are little different from an urban area, and in other cases, they cover broad regions that have little relation to a single urban settlement; comparative statistics for metropolitan areas should take this into account. The term metropolitan can also refer to a [[county]]-level [[municipal government]] structure, with some shared services between a central city and its suburbs, which may or may not include the entirety of a metropolitan area. Population figures given for one metro area can vary by millions.

There has been no significant change in the basic concept of metropolitan areas since its adoption in 1950,<ref>{{cite web|url=https://www.census.gov/population/www/metroareas/aboutmetro.html|title=About Metropolitan and Micropolitan Statistical Areas |publisher=U.S. Census Bureau, Population Division |access-date=27 April 2016 |url-status=dead |archive-url= https://web.archive.org/web/20110925114107/https://www.census.gov/population/www/metroareas/aboutmetro.html |archive-date= Sep 25, 2011 }}</ref> although significant changes in geographic distributions have occurred since then, and more are expected.<ref>{{Cite journal |title=Alternative Approaches to Defining Metropolitan and Nonmetropolitan |date=December 21, 1998 |journal=Federal Register |volume=63 |issue=244 |publisher=OMB |url=https://www.whitehouse.gov/omb/rewrite/fedreg/msa.html|archiveurl=https://web.archive.org/web/20090723114246/http://www.whitehouse.gov/omb/rewrite/fedreg/msa.html|url-status=dead|archivedate=July 23, 2009}}</ref> Because of the fluidity of the term "metropolitan statistical area", the term used colloquially is more often "metro service area", "metro area", or "MSA", taken to include not only a city but also the surrounding suburban, exurban and sometimes rural areas, all of which the city is presumed to influence. A '''polycentric metropolitan area'''<!-- bolded because this term redirects here --> contains multiple urban agglomerations not connected by continuous development. In defining a metropolitan area, it is sufficient that a city or cities form a nucleus with which other areas have a high degree of integration.

A metropolitan area is commonly known and characterized by a high concentration in [[tertiary sector of the economy|service sector]] labor and enterprises.<ref>{{cite web |url=https://www.weforum.org/agenda/2015/07/how-services-increased-the-economic-gap-between-the-rural-and-urban-us/ |first1=Alexandra |last1=Lopez-Cermeño |date=Jul 14, 2015 |title=How services increased the economic gap between the rural and urban US |publisher=[[World Economic Forum]]|access-date=2022-04-19}}</ref><ref>{{cite journal |title=The Development of Metropolitan Economy in Europe and America |journal=The American Historical Review |date=1922 |volume=27 |issue=4 |pages=695–708 |doi=10.2307/1837536 |doi-access=free |jstor=1837536 |last1=Gras |first1=N. S. B. }}</ref> [[Macroeconomics]] views metropolitan areas as [[trade]] regions of economic significance.<ref>{{Cite journal |last=Olberding |first=Julie Cencula |date=Aug 2002 |title=Diving into the "Third Waves" of Regional Governance and Economic Development Strategies: A Study of Regional Partnerships for Economic Development in U.S. Metropolitan Areas |url=https://journals.sagepub.com/doi/10.1177/089124240201600305 |journal=Economic Development Quarterly |language=en |volume=16 |issue=3 |pages=251–272 |doi=10.1177/089124240201600305 |publisher=SAGE Journals |access-date=28 April 2023 }}</ref>

Since, presently, urban data are based on arbitrary definitions that vary from country to country and from year or census to the next, making them difficult to compare, an Urban Metric System (UMS) has been conceived that could correct the problem,<ref>{{cite web |url=https://authors.elsevier.com/sd/article/S1757-7802(24)00342-1|title=Estimating urban sprawl standards by means of the Urban Metric System |last1=Tellier |first1=Luc-Normand |last2=Quesnel |first2=Frédéric |last3=Bur |first3=Justin |publisher=Regional Science Policy and Planning |date=November 2024 }}</ref> since it allows computing the urban area limits and central points, and it can be applied in the same way to all past, present and future population and job distributions. 
It is based on vector field calculations obtained by assuming that, in a given space, all inhabitants and jobs exert the same attractive force ''A'' and repulsive force ''R''. The net force (''A'' - ''R'') exerted by each inhabitant or job is given by [1/(1 + ''d'')] - [1/( ''β'' + ''d''/2)], where ''d'' = distance and ''β'' is the only parameter. 
UMS distinguishes the following types of urban areas, each type corresponding to a given value of ''β'':
{| class="wikitable"
|+
!
!Urban area
!Distance at which the attractive force = the repulsive force 
!Value of ''β''
|-
!1
!Central city
!10 km
!6
|-
!2
!Agglomeration
!20 km
!11
|-
!3
!Metropolis
!40 km
!21
|-
!4
!Patropolis
!80 km
!41
|-
!5
!Megalopolis
!160 km
!81
|-
!6
!Urban system
!320 km
!161
|-
!7
!Urban macrosystem
!640 km
!321
|-
!8
!Continental system
!1,280 km
!641
|-
!9
!Intercontinental system
!2,560 km
!1,281
|-
!10
!World system
!5,120 km
!2,561
|}

UMS has been applied to some Canadian cases since 2018, but the data presented in this article are still based on the various existing national definitions, which are disparate.