Study On The Evolution Characteristics Of Spatial Pattern Of The Central Yunnan Urban Agglomeration

Urban agglomerations have become the main form of regional development in China.As the most economically developed region in Yunnan Province,urban agglomerations in central Yunnan still have problems such as large contradictions in supply and demand of land resources,fragile ecological environment,large degree of economic development differentiation,and unreasonable industrial structure.The scientific formulation of spatial planning plays a vital role in the urbanization process of the central Yunnan urban agglomeration and even Yunnan province.At present,the research on the spatial pattern of urban agglomerations is mainly based on feature description,the depth of the analysis of the driving mechanism is not enough,and there are few studies on the division of urban areas.The study introduces the comprehensive compactness of urban agglomerations as an indirect indicator of hierarchy analysis of urban agglomerations,and constructs a comprehensive evaluation model of urban centrality and a comprehensive evaluation model of urban spatial connections to determine the regional central cities and their cluster cities.The study takes the 46 districts and counties(including county-level cities)of the central Yunnan urban agglomeration as the object,explores the evolution characteristics and driving mechanism of its spatial pattern,and puts forward opinions and suggestions for the formulation of a more reasonable central Yunnan urban agglomeration development plan.Using ENVI remote sensing image analysis method,Arc GIS spatial analysis method,SPSS mathematical statistical analysis method.Based on statistical data and remote sensing image data in 1994,2002,2010 and 2018.From the three aspects of urban agglomeration’s hierarchy,spatial connection and land expansion process,the spatial pattern evolution characteristics of central Yunnan’s urban agglomeration are studied.The driving mechanism is analyzed from the geographical location factors,economic development factors,and government regulation factors.The research content is mainly divided into four points:(1)In terms of hierarchy,the central Yunnan urban agglomeration presents a "single-center" structure,and thedevelopment speed of secondary cities is accelerating,but there is still a significant gap from the first city.The core position of the four districts of Kunming It will not change in a short time.From 1994 to 2018,the top ranking,the city size Gini index,and the overall compactness of urban agglomerations increased from 1.317,0.360,and-0.07 to2.454,0.389,and 0.66,respectively.Various production factors are highly concentrated in the first cities,with a prominent core position.(2)In terms of spatial connection,the centrality index and spatial connection intensity of central Yunnan cities have been continuously enhanced with the development of economic level and transportation construction.The more stable Kunming Metropolitan Area,Yuxi Metropolitan Area,Qujing Metropolitan Area and Gejiu Urban Area,Chuxiong Metropolitan Area have emerged.The district has taken shape.The scope of the urban area calculated from the comprehensive evaluation model of urban centrality and the comprehensive evaluation model of urban spatial connection is basically consistent with the "Central Yunnan Urban Cluster Planning(2016-2050)".This model can be better applied to the division of urban area groups.(3)In terms of land expansion,cities of different scales and grades show obvious stage characteristics.The urban economy has undergone three stages of development: the "agricultural economic period-the market economic period-the new economic period",and the expansion of urban land shows a change in land expansion of "rapid rule expansion-rapid irregular expansion-slow rule expansion" In the process,the morphological characteristics of the land also correspond to the three stages of "single point extension-multipoint extension-single point filling".(4)In terms of driving mechanism,the evolution of the spatial pattern of urban agglomerations in central Yunnan is mainly affected by mountainous terrain,traffic road directions,economic development,industrial structure,and government regulation and control factors,showing the characteristics of government leadership,economic driving,and environmental constraints.The evolution of hierarchy system and spatial connection is mainly affected by population composition,industrial structure,and development guidance of the Central Yunnan Urban Agglomeration Planning.The characteristics ofurban land expansion in central Yunnan are mainly affected by the terrain of the plateau and mountains and the guiding ideology of the Outline of Yunnan Province’s National Economic and Social Development Plan.Research conclusions and recommendations:(1)Speed-up the development of secondary cities.There is still a large gap between the first and secondary cities in the central Yunnan urban agglomeration.In order to guide the central Yunnan urban agglomeration to a more beneficial "multi-center" structure,attention should be paid to stimulating the industrial and economic development of the secondary cities in the urban agglomeration and improving the secondary Regional driving capacity of first-class cities.(2)Improve the level of economic development and transportation construction of urban agglomerations.The overall economic level of the central Yunnan urban agglomeration is low,and the strength of the economic links between cities is insufficient.At the same time,due to terrain restrictions,transportation construction is difficult,and the overall stability of the urban agglomeration is insufficient.It is necessary to speed up the transformation of industrial structure,increase the construction of transportation facilities,and improve the tightness of spatial linkages in urban agglomerations.(3)Guide the compound development of urban land in central Yunnan.From 1994 to 2018,the type of urban land expansion in central Yunnan has changed from an extended type to a filled type,but the problem of unbalanced land supply and demand is still serious.The problem of land shortage can be solved from the aspects of developing compound land,reusing land,and strictly controlling land development.