(
United States) (top) and
Taiheiyō Belt (
Japan) (bottom) A megalopolis may also be called a megaregion. "Megalopolis" and other similar terms have been used by different scholars and countries to describe similar spatial forms. in
Brazil A megalopolis, following the work of Gottmann, refers to two or more roughly adjacent
metropolitan areas that, through a commonality of systems—e.g., of transport, economy, resources, and ecologies—experience a blurring of the boundaries between the population centers,) is a clustered network of big cities. Gottmann defined its population as 25 million, while Doxiadis defined a small megalopolis a similar cluster with a population of about 10 million. America 2050, a program of the Regional Plan Association (RPA), lists 11 megaregions in the United States and Canada.
Megaregions of the United States were explored in a July 2005 report by Robert E. Lang and Dawn Dhavale of the Metropolitan Institute at
Virginia Tech. A later 2007 article by Lang and Nelson uses 20 "megapolitan" areas grouped into 10 megaregions. The concept is based on the original "Megalopolis model". In Brazil, the term has a legal meaning, different from the English word
megaregion:
mesoregions of Brazil () and
microregions of Brazil (). In China, the official term corresponding to the meaning of "megalopolis" is '' (), which, in Chinese, was originally coined by Yao Shimou and literally means "city cluster". A "city cluster" is defined as "[a]n area in which cities are relatively densely distributed in a certain region". In an older standard, the term was mistranslated as "
agglomeration". In the latest standard terminologies of both economics and urban planning, is translated as "city cluster", replacing "agglomeration".
Megalopolises in China have become the subject of national government planning. 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, 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. UMS 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 (including "Megalopolis"), each type corresponding to a given value of
β: 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. ==List of megalopolises==