What smart cities and sponge cities are there in the urban system?

Smart city, sponge city and urban system are not a concept.

1. Smart city uses information and communication technology to perceive, analyze and integrate the key information of urban operation core system, so as to make intelligent responses to various needs including people's livelihood, environmental protection, public safety, urban services and industrial and commercial activities. Its essence is to use advanced information technology to realize the intelligent management and operation of the city, so as to create a better life for people in the city and promote the harmonious and sustainable growth of the city.

2. Sponge city is a new generation of urban storm flood management concept, which means that the city has good "elasticity" in adapting to environmental changes and responding to natural disasters caused by rain, and can also be called "water elastic city". The international term is "low-impact development rainwater system construction". Absorb water, store water, seep water and purify water when it rains, and "release" the stored water for use when necessary. The function is to effectively alleviate the urban heat island effect and make the urban pavement no longer warm up.

Third, the urban system is an urban group organization in a certain region, with the central city as the core, and cities of different natures, scales and types are interrelated and interacting with each other. It is the overall situation of the spatial layout of different levels of cities and towns that are interrelated and play various functions in a certain area.

Urban system is the basic skeleton system of economic zone, the product of regional social and economic development to a certain stage, and the most effective organizational form for cities to drive regions.

The concept of urban system was formed in the 1920s and 1960s. Function: an important symbol to measure the development level of a country. Reason: the product of social and economic development to a certain stage.

There are four types of urban systems:? Pyramid type? Polymorphism? Network type? Band type

1. Pyramid type: with a big city or megacity as the core, the surrounding small and medium-sized cities are distributed around the big city or megacity in a ring shape at different distances. Their development and functional characteristics depend on the development of megacities and megacities. With the development of this urban system, the first problem to be solved is to control the scale of big cities and megacities, develop sub-centers and disperse the functions of big cities and megacities.

2. Polymorphism; The characteristics of multi-core city system are that there are many core cities in the region with the same scale, gravity and influence, which play a spatial role in other small and medium-sized cities in the region; The relationship between cities in the region is relatively loose, and there is no strict compliance between them; The spatial distribution of cities in the region is relatively scattered and far away.

3. Network type: the network type urban system refers to the similar nature and scale of the core cities in the region, and the interaction between them is difficult to distinguish; There are close links between core cities and between core cities and other cities.

4. Belt: The belt-shaped urban system refers to the belt-shaped urban system formed in the areas along the traffic trunk lines and river basins, which is arranged in a belt shape in space and connected end to end.