The city is an integral system. In his body, such structural components as the population, material and material environment, natural environment, social, spiritual, psychological environment are allocated. There are two main classes of urban models, and five models of urban systems. These are the so-called concentric zones, the resettlement of the inhabitants according to the level of well-being and the functions of cities.

1. The isolated state of Thunen:
2. Concentric model of Burgess.
3. The Hoyt Sector Model.
4. Multi-nuclear model of Ulman-Harris.
5. Factor ecology.

Five models of the city system:

1. Model of the central places of the Crystal — Lyosha.
2. Zipf’s rule.
3. Diffusion of the innovations of the Hagerstrand.
4. Gravitational models and potential field theory.
5. Model of the main potentials.

According to the theory of concentric zones (Chicago School) in the spatial structure of the city are:

— the central business district in which the main commercial enterprises, shops, entertainment institutions, administrative institutions are located;

— a mixed zone where residential buildings and commercial enterprises coexist;

— the working area where the workers’ dwellings are located;

— a residential zone of middle class, where mainly single-family mansions are concentrated, in them live officials and people of intellectual labor;

— a privileged zone where representatives of the higher and middle class live, high-ranking administrators and the creative elite, rather, a suburb, and not a city.

According to the «sectoral» theory (Hoyot), the focus is on the analysis of the city’s sectors in connection with the development of transport routes and already built-up areas. Structure — sectors of different scale and quality of the environment with the top in the center of the city. The main factors of sectoral dynamics are the cost of land and transport arteries. Sectors develop along transport routes, and the quality and functional profile of the territory is determined by the price of land, which depends, first of all, on the prestige of the place.

Multi-core model of the city (Harris and Ulman 1945): there are various centers on the territory of the city, around which are formed homogeneous in their internal composition, but diverse in character and function of the territory — administrative, financial, trade, recreational, etc. The most striking example is London . The tendency of urban development is also seen: the older and larger the city, the more nuclei there are in it, and they are more diverse. The historical center turns into one of the nuclei. The actual center, the prestigious place can become other nuclei, there is a dynamic, changing the place of the central zone, inversion of the territory along the axis «center-periphery.»

Today, simultaneously with the elaboration of strategic planning areas, territorial planning schemes are being developed. These documents have become an obligatory component of the management system in all levels — from municipalities to the state level.

Currently, urbanization is due to the scientific and technological revolution, changes in the structure of productive forces and the nature of labor, deepening the links between act Common features of urbanization in the world are:

— Preservation of interclass social structures and groups of the population, division of labor that fixes the population in the place of residence;

— Intensification of socio-spatial links that determine the formation of complex settlement systems and their structures;

— Integration of rural areas (as a village settlement sphere) with urban and the narrowing of the village’s functions as a socio-economic subsystem;

— High concentration of such activities as science, culture, information, management, and increasing their role in the country’s economy;

— Intensified regional polarization of urban economic and, as a result, social development within countries.

Features of urbanization in developed countries are manifested in the following:

— Slowing the growth rate and stabilizing the share of the urban population in the total population of the country. The slowdown is observed when the share of urban population exceeds 75%, and stabilization — 80%. This level of urbanization is noted in the UK, Belgium, the Netherlands, Denmark and Germany;

— Stabilization and inflow of population to selected regions of rural areas;

— Cessation of the demographic growth of metropolitan agglomerations, which concentrate the population, capital, socio-cultural and administrative functions. Moreover, in recent years, in the metropolitan agglomerations of the United States, Britain, Australia, France, Germany and Japan, there has been a process of deconcentration of production and population, manifested in the outflow of population from agglomeration nuclei to their outer zones and even beyond agglomerations;

— The change in the ethnic composition of cities due to the continuing migration from developing countries. The high birth rate in migrant families significantly affects the decrease in the proportion of the «titular» population of cities;

— Placement of new jobs in external areas of the metropolitan area and even beyond.

Modern urbanization has led to a deepening of social and territorial differences. A kind of payment for the concentration and economic efficiency of production in the conditions of urbanization has become the regionally-social polarization between the backward and advanced regions, between the central regions of the cities and the suburbs, which is constantly reproduced in the most developed countries; the emergence of adverse environmental conditions and, as a result, the deterioration of the health status of the urban population, especially the poor.

Picture 1 presents schematically the main advantages and disadvantages of urbanization to date.

Picture 1. The main advantages and disadvantages of modern society urbanization

 Advantages of urbanization:

1) Development and growth of cities, growing as if separately — point concentration; The city accumulates potential, complicates its functional and planning structures, but further expansion is difficult because of the limited territorial resources;

2) Formation of agglomerations — post-urban stage of settlement development; characterized by the emergence of a galaxy of settlements on the basis of a large city. The agglomeration has two main properties — the proximity of the settlements that form them and the complementarity. Agglomerations play a leading role in all developed and in a number of developing countries;

3) Formation of megacities and the formation of a supporting framework in the resettlement. The supporting frame is an urbanized portrait of a country or region. It is caused by a combination of nodal (city and agglomeration) and linear (highway and other transportation lines). Where they are brought together and the territory is covered by zones of their influence, urbanized areas are formed. The formation of the supporting framework indicates the manifestation of two tendencies in the development of settlement: centripetal and linear-regressive.

Despite a number of advantages, urbanization creates a number of problems, briefly illustrated in picture 2.

1) The economic problem is that if in the first time the concentration of industry gave an additional effect due to the broad opportunities for combining and cooperating, then later negative aspects emerged on the forward plan, such as traffic congestion in cities, difficulties in water supply, environmental problems. The solution to this problem is the need to transfer industry from cities that perform such functions as research and development and financial and management functions.

2) Environmental problems. Cities concentrate all kinds of environmental pollution, having a huge impact on the territory.

3) Social problems are manifested in sharp differences in the quality of life in cities and peripheral areas, in social contrasts within large cities.

For the economies of countries, well-managed urbanization brings more pluses than minuses. The closeness and diversity of people can stimulate innovation and create new jobs, ties between cities historically form the basis of global trade, and by reducing the need for transport, the economy becomes more environmentally friendly.[1]

Picture 2. The main problems of urbanization

By 2030, there will be 41 cities in the world, in which 720 million people will live. And by 2025, 600 cities will provide more than 60% of world GDP growth. But if before the 1970s. economic growth in cities was driven by industrialization, but now those who invest in human capital and the development of creative sectors benefit from competition.[2]

A turning point in urbanization occurred in 2007, when urban residents, according to the UN, in the world became more than rural. In 2014, the citizens were already 54% (about 3.9 billion people). And by 2050 in urban agglomerations will already live 66% of all people on the planet (100 years before 70% of the population lived outside of cities).

The highest level of urbanization in the United Nations is recorded in Latin America, the Caribbean and North America: 8 out of 10 people live in cities. A little less urbanized Europe — 73% of urban residents.

Africa and Asia are still the «rural» regions themselves (40% and 48% of urban residents, respectively), but it is they who until 2050 will provide 90% of the total increase in the number of townspeople.

In 1990, the largest in terms of population were Japanese Tokyo and Osaka and American New York. Now the world has 28 megacities — cities with a population of more than 10 million people. Now all three largest cities in the world are in Asia: Japanese Tokyo with 38 million people, Indian Delhi (25 million inhabitants) and Chinese Shanghai (23 million). These same cities will retain their leadership by 2030.

At the same time, the population of Delhi will double, and in Shanghai people will be 4 times more, the UN predicts.

«Urbanization will become one of the biggest driving forces of global economic growth in this century,» McKinsey experts say. The UN calls cities an important driver of poverty reduction — not only in the agglomerations themselves, but also in rural areas.

Historically, the process of urbanization is associated with economic and social factors. People in search of a better life are moving from a village to a city where a large part of the national economy is concentrated, with a higher level of literacy and education, more opportunities to use transport and social services, more employment options. The basis of urbanization is economies of scale and productivity, which makes cities more productive.

Urbanization by itself does not lead to economic success, but the economic success of cities can be very important for the country, wrote in 2016 the World Bank’s chief economist for Russia, Apurva Sangi, in an article for Vedomosti.

Now 600 largest cities account for more than half of world GDP, or $ 30 trillion. It is expected that from 2007 to 2025 the aggregate GDP of 600 cities will increase by $ 34 trillion, which will provide more than 60% of the growth in global GDP. The most productive will be the top 100 cities: they will account for 35% of world GDP growth (and 38% of world GDP).

In terms of GRP, New York, Tokyo, Shanghai, Beijing and London will lead the cities. And the growth in the first two places will be Chinese Shanghai and Beijing, will close the top three New York, London and Tokyo will be only on the 12th and 20th places. In the top 25 of the «hot regions» will be Moscow: on the contribution to the growth of world GDP, it will be on the 17th place by 2025.

In Russia, the number of urban residents will decrease, waiting for the UN, by 7 million people by 2030. According to Rosstat, as of January 1, 2017, there were 109 million townspeople in Russia.

In 20 of the world’s richest cities, more than 75% of the largest companies are registered. More favorable conditions for doing business, large cities attract more talent and investors. At the same time, consultants offer companies that are looking for new opportunities in the world economy, pay attention not only to megacities, but also to other major cities, whose role in global growth will increase.

By the year 2025, more than a quarter of the working-age population (15 to 64 years), 15% of children (under 15 years) and 35% of the elderly population (aged 65 and over) will live in 600 cities. The growth of the able-bodied population will be provided first of all by the cities of China and South Asia — two thirds of 310 million people in 600 cities.

For the years 2007-2025. in 600 cities 250,000 new households will be formed, which will increase the demand for transport, housing, household appliances and other goods and services.

According to the authors of the report of the Davos Forum The Risks of Rapid and Unplanned Urbanization in Developing Countries, the process of urbanization requires additional investments, primarily in improving the quality of urban infrastructure. Infrastructure development does not always keep up with the expansion of cities. According to the estimates of the Organization for Economic Cooperation and Development, the costs of providing the global infrastructure for electricity, road and rail transport should reach $ 71 trillion by 2030. — approximately 3.5% of global GDP. Most of these investments are needed for developing economies.

81% of the total consumption of goods and services will fall to cities by 2030, with cities providing 91% of the total $ 23 trillion growth (+ 3.6% annually) that will occur during this time and the larger the city, the faster the consumption there increases

Another difficulty is the pressure on the housing market, arising from the growing demand. The policy on ensuring the affordability of housing for urban citizens should include both the limitation of excessive lending and the optimization of land use, the authors of the report of the Davos Forum note. The UN Urban Agenda New Urban Agenda (NUA) is trying to solve the housing problem by promoting home ownership and various options for renting (for example, cohousing). One of the principles of the NUA housing policy is the joint work of the state and the private sector to provide housing.

In most countries where urbanization is taking place, the health of citizens has improved through access to health services. But rapid and unregulated urbanization combined with high population density, poverty and lack of infrastructure can contribute to the faster spread of infectious diseases. As of 2015, nearly 700 million urban residents did not have adequate sanitation. On the other hand, urbanization can create an additional risk of «lifestyle diseases» — associated with unhealthy diet, lack of physical activity, air pollution.

Finally, a new wave of urbanization can no longer bring economic growth, the ASEAN report presented this year says. For example, although the economies of Southeast Asia grew together with urbanization, growth in this region was very uneven: in Singapore, labor productivity (economic output) is $ 66,900 per person, and in the capital of Indonesia, located nearby Jakarta, only $ 10,000 .

XXI century. — this is the age of creative, smart cities and «cities of knowledge», write Paul Salmon and Nicholas Stevens from the University of Sunshine Coast on the website of the Davos Forum. Such cities focus on the use of human resources, social capital, education, innovation, communications and digital technologies.

The very concept of «creative class» in the early 2000s was introduced by the American economist, Ph.D. Richard Florida. According to his theory, the key to successful economic development of cities and regions in the post-industrial era will be the activities of people who can generate new ideas, create new types of business and apply new approaches to already established processes. To the creative class, Florida refers the employees of the scientific and technological sphere, art, culture, entertainment and media, education, health and law.

In 18 countries, the creative class is more than 40% of all employees. Most of all (54%) — in Luxembourg, then — Bermuda with 48%, and in third place — Singapore (47%)

David Ayvan from the University of Michigan last year presented the results of a multi-year study of 300 small towns in 22 US states. Ivan wanted to understand what makes this or that place «cool» (what makes a place cool). The main conclusion is that the same concept of creative capital works for small cities: small American cities, which can be called class, have shifted the focus from attracting companies to attract talent and from investing in physical infrastructure to invest in creative infrastructure. They engaged in the development of the ecosystem for entrepreneurs, invested in human capital, actively supported the development of long-term social networks and local communities (including for schoolchildren — research showed that those who have fond memories of a small homeland, are then more actively involved in it fate and return more often), developed the urban environment and created places in which people want to be, and actively encouraged the initiatives of the inhabitants, however modest they may be.

Since 2004, The Martin Prosperity Institute estimates these three country parameters by ranking them according to the value of the Global Creativity Index. In 2015, Australia, the USA and New Zealand were the leaders.

The Institute found a relationship between economic growth and the creativity index, finding that each of the three «T» correlates with the value of GDP per capita. The highest correlation coefficient is in tolerance, followed by talent, and only in the third place is technology. In oil economies, where «wealth can be pumped out of the ground,» the influence of the three «T» on economic growth is small.

The authors of the index found a correlation between the three «T» and urbanization: the higher the level of urbanization in the country, the more creative capital there is there. The strongest ratio with urbanization is talent, technology — on the 2nd line, and tolerance — on the third.

         The World Bank uses the notion of «competitive cities». It calls the three main areas of action that the bank has discovered in the most competitive cities. First, such cities develop primarily the tradable sectors of the economy — machine building, light industry, etc. Secondly, such cities are being sought from other levels of government so that they do what is beyond the power of city governments (he gives an example Colombian city of Bucaramanga: there authorities found that the main deterrent to the growth of local enterprises is the low level of transport development, and used the results of this study to lobby the city’s interests in national government).

And finally, competitive cities really work, he writes: they implement strategies in life. «The main tool is the city’s budget: cities are building their budget so as to finance priority areas,» he writes and cites the example of the American Baltimore, where each department and every agency is obliged to prepare proposals explaining the need for budgetary allocations and explaining how the work is related to the implementation of six agreed citywide priorities.

In modern Russia, the process of urbanization is also associated with serious contradictions. The geography of Russian cities is well reflected, with the specifics of the country: the vastness of the space it occupies formation of the stateterritory and geographic course of urbanization, divisive division into parts, differing from each other in many respects, including the degree of mastery level of social and economic development and form urban systems.

Russia is a country with a high level of urbanization — 73.7% of the population live in cities and towns. From the 109 314 000 urban residents in cities with a population of 100,000 or more, there are 73 228 000 people, which is more than 50% of the total population of the country. In turn, 50.84% ​​of the population lives in small and medium cities, urban-type settlements, rural settlements.[3]

Currently, there are several methods for assessing the level of urban agglomeration. They, as a rule, reflect integral indices on the basis of private indicators. The most famous of them are:

1. The methodology of the Institute of Geography RAS, which takes into account the following indicators:

— Population size (should be ≥ 250 thousand inhabitants);

— Agglomeration development factor (should be ≥ 1);

— Transport accessibility of the agglomeration core.

2. The methodology of the Central Research Institute of Urban Planning, complements the methodology of the Institute of Geography of the Russian Academy of Sciences by such indicators as the two-hour transport availability of the core, the agglomeration coefficient and the agglomeration index.
3. The methodology for estimating the aggregate potential of a specific agglomeration proposed by AA Ugryumova.[4]

The tendency to property polarization of the population within the urban communities leads to the segregation of the poor population, displacing it to the «roadside» of city life. The economic crisis and political instability stimulate unemployment and internal migration, as a result of which, because of the excessive influx of people, much more people live in many cities than they are able to «digest». The growth of the population in cities, far outstripping the demand for labor, is accompanied not only by the absolute, but sometimes by the relative expansion of those layers that do not participate in modern production. These processes lead to an increase in urban unemployment and the development in the cities of the informal sector of the economy, engaged in small-scale production and services. In addition, there is a noticeable increase in the criminal sector, which includes both the «shadow» economy and organized crime.

Whatever it was, urban life and urban culture have become an organic environment of social living. At the beginning of the XXI century. The majority of Russians are indigenous citizens. They will set the tone for the development of society, and how the social management systems are formed, how the social environment will change, the life of new generations will depend.

[1] https://www.vedomosti.ru/partner/articles/2017/05/24/691328-buduschee-gorodah.

[2] https://realist.online/article/kakie-posledstviya-neset-urbanizaciya.

[3] Шевелева Р. Н. Современные процессы урбанизации: характеристика, влияние на региональное развитие [Текст] // Проблемы современной экономики: материалы IV Междунар. науч. конф. (г. Челябинск, февраль 2015 г.). — Челябинск: Два комсомольца, 2015. — С. 130-133. — URL https://moluch.ru/conf/econ/archive/132/7093/ (дата обращения: 16.07.2018).

[4] Шмидт Андрей Владимирович, Антонюк Валентина Сергеевна, Франчини Альберто. Городские агломерации в региональном развитии: теоретические, методические и прикладные аспекты // Экономика региона. 2016. №3. URL: https://cyberleninka.ru/article/n/gorodskie-aglomeratsii-v-regionalnom-razvitii-teoreticheskie-metodicheskie-i-prikladnye-aspekty (дата обращения: 16.07.2018).