Sub-space Evaluation Of Land Carrying Capacity And Population Estimation Of Megacities

Land resources are the basis for human survival and maintenance of life.In the process of rapid urban development,population surges,and the contradiction between urban land and population becomes an important factor restricting social development.As the economic center of China,Shanghai bears the functions of regional economy,politics and culture.It is of great significance for Shanghai and even China to study the land and population carrying capacity of Shanghai,optimize the land use of Shanghai and promote the healthy development of the city.This paper takes Shanghai,China's megalopolis,as the research object.Firstly,combining with the status quo of land use in Shanghai,Shanghai is divided into three subspaces: urban space,agricultural space and ecological space.Secondly,according to the characteristics of the subspace,the evaluation index system of the bearing capacity of land in Shanghai was constructed.The entropy value method was used to calculate the index weight,and the index weight was added to evaluate and analyze the carrying capacity of the sub-space land in Shanghai.At the same time,the index of carrying capacity of each sub-space in Shanghai was divided into five grades by the method of natural discontinuance,and the area of each grade was counted.Finally,by studying the population characteristics of megacities at home and abroad and combining with the specific situation of Shanghai,the population carrying capacity per unit area of each land use subspace was determined,and the population carrying capacity of Shanghai was estimated.The results show that the distribution of the bearing capacity of the land in Shanghai gradually decreases from the downtown area.It is estimated that the carrying capacity of land population is between 27.3907 and 30.4341 million,among which the urban space is the main carrying space of the population in Shanghai,with a carrying capacity of 21.65 to 23.87 million.Combined with the population estimation results and the current population status data of Shanghai,it shows that although there is still a certain amount of population carrying space in Shanghai as a whole,the population distribution is seriously out of balance,and the population carrying pressure in the central urban areas is large.Putuo district,yangpu district and jingan district have an overpopulation of more than 600,000 people.The population distribution in the inner suburbs is reasonable,which is basically within the carrying population range.The outer suburbs have great population carrying potential,and chongming district still has enough capacity to carry 2 million people.In general,Shanghai should reasonably allocate population distribution,strengthen policy guidance,optimize the spatial distribution of Shanghai development,and promote the population transfer to the suburbs.This paper introduces the concept of spatial division,calculates the bearing capacity of land in Shanghai by spatial classification based on GIS spatial analysis method,and enriches the research perspective and method of the bearing capacity of land in megacities.On the other hand,the population carrying capacity of Shanghai is estimated by space and region,which is helpful to reveal the internal differences of the population carrying capacity of Shanghai,and provides a referable decision basis for the rational control of the urban population growth in Shanghai,the optimization of land use and the promotion of sustainable development.