Study On Spatial-temporal Evolution Of Urban Form And Land Use Patterns In Kunming City

The evolution of urban spatial form and the course of urban land use change are the concentrated reflection of spatial layout and land use structure change in the process of urban development.The analysis of urban form and land use change can reflect the change of important geographical elements in the city.As a complex giant system,it is difficult for general geometric methods to describe its morphological characteristics comprehensively and objectively.Fractal geometry provides theoretical support for solving complex urban spatial morphology problems.The self-similarity of urban land use patterns also provides the possibility of using fractal method to solve urban land use problems.As a typical plateau city in southwest China,Kunming is a type of city worthy of in-depth study.By using fractal theory and landscape ecology theory,the internal and external spatial form of the city covered by complex exterior can be removed,and its internal evolution characteristics and laws can be revealed.Based on the research of urban form and land use structure,this paper interprets the remote sensing images of Kunming in 2002,2009 and 2017 by human-computer interaction based on ArcGIS platform,and obtains five kinds of land use types of vector maps and raster maps: residential,public management and public service,industrial logistics warehousing,commerce,green space and plaza.The fractal analysis of urban form in three periods is carried out,and the box dimension is used to analyze the urban boundary,revealing the evolution characteristics of spatial form;the box dimension and radius dimension are used to analyze the shape of urban functional land use in different periods,and the landscape pattern index in landscape ecology isused to analyze the spatial distribution of functional land use,revealing the soil in the development process of Kunming.Finally,based on the above results,the evolution mechanism and dynamic mechanism of spatial morphology fractal characteristics of Kunming's overall urban development and land use classification are analyzed,and the sustainable development of the city is considered in combination with relevant urban spatial morphology theory.The conclusions are as follows:1.It is feasible to use fractal model to study the urban form and land use pattern of plateau.The empirical study of Kunming City shows that the results of the study conform to the law of negative fractal power,which fully proves that the fractal model is feasible in the morphological study of high-prototype cities.2.The evolution law of urban form and land use pattern in Kunming conforms to the fractal dimension inclusive principle.In the study,Kunming urban morphology has fractal characteristics,showing obvious self-similarity and self-organizing optimization trend.The fractal dimension changes of urban boundary and urban internal land use structure show that Kunming city is spiraling up and developing in an orderly and chaotic state,both in general and in part,exterior and interior.The fractal dimension of the whole urban spatial form in the third phase is larger than the fractal dimension of all kinds of functional land use,which conforms to the fractal dimension inclusive principle of urban form.3.The urban form of Kunming has gradually been ordered,but it has not yet reached a reasonable urban form.The fractal dimension of Kunming's urban boundary is calculated by box dimension in fractal theory.Combining with the development of Kunming in recent15 years,the fractal characteristics of Kunming's urban form are comprehensively analyzed.The change of box dimension in three years is 1.6186-1.7709-1.8486,which indicates that Kunming's urban boundary is gradually complex and irregular,but it has not yet reached a reasonable urban form of 1.7.4.The land in Kunming has fractal characteristics.The degree of agglomerationof different types of land gradually decreases,and the trend of patch equilibrium distribution increases.The box dimension and radius dimension of fractal theory are used to analyze the spatial and temporal evolution of urban land use pattern in Kunming City.The results show that the box dimension of residential land has been at a high level in five types of urban functional land,and shows a trend of increasing first and then decreasing gradually.This shows that under the unified planning of the government,the space of residential land is constantly filled up,showing compactness.Spatial layout.The spatial distribution of commercial land,public land and green space shows an increasing trend,but because of the lack of close links within the terrain,the box dimension is low,which indicates that the terrain in these three periods is in a chaotic state of disorder,loose and not large-scale.Through the analysis of the radius dimension of several types of land,it can be seen that the attenuation rate of land use density in Kunming is in turn commercial land,residential land,green land,public land and industrial land.Commercial land is mostly concentrated in the urban center,and industrial land is mostly concentrated in the periphery of the city.Based on the theory of landscape ecology,the landscape pattern index was selected from two levels of patch type and landscape level to study the urban land use pattern.The results show that the fragmentation degree of various types of land increases with the passage of time,the shape of patches becomes more and more complex,the degree of reunification of different types of functional land is lower,and the landscape uniformity,that is,the area distribution,is more balanced.5.The evolution of urban form and land use pattern in Kunming is influenced by many factors.Influenced by many factors,such as regional physical and geographical conditions,policy orientation of economic development,industrial layout structure and basic transportation facilities,the external form of Kunming city is becoming more and more complex and irregular,and the land use within the city is gradually orderly,which is in a better development situation.However,urban development is still facing the constraints of insufficient construction land.In the future,attentionshould be paid to combining urban characteristics,industrial transformation and human-land coordination,adjusting the unreasonable land use structure,optimizing the existing land distribution,and making the city sustainable development.