Urban Spatial Form And Driving Force Of Built-up Areas In Guiyan

During the rapid development of urbanization in mountainous areas,a large number of hills with different scales are left in the artificial Built environment in the form of island patches,forming a mountainous city type with cities and mountains inlaid in the mountains and mountains in the city.In order to explore the spatial morphological characteristics of mountainous cities in the context of urbanization and reveal various urban problems,the built-up area of a typical mountainous city in central Guizhou(Guiyang City)was taken as the study area,and the boundary characteristics of urban built-up areas were analyzed using the methods of expanded area,compactness index,landscape expansion index,and spatial center of gravity shift analysis,based on the data of phase III high-resolution remote sensing data and building census data,In order to reveal the evolution characteristics of the boundary morphology of the expansion of mountainous urban construction land and the interrelationship between urban residual mountains and urban boundary morphology,and provide a reference basis for the delineation of urban development boundary control lines;Using kernel density analysis,landscape pattern index and Space syntax,the morphological characteristics of urban buildings and urban roads on the two-dimensional level are explored;Based on the building census data,mountain visual interpretation data and DEM elevation data,the undulation measurement,cold and hot spot analysis and the selection of four three-dimensional landscape indicators,namely,the average height of buildings,the standard deviation of building height,the average building volume and the building Floor area ratio,are used to analyze and reveal the spatial morphological characteristics of urban buildings and terrain on the three-dimensional level,which can ensure the effective play of the ecological service function of urban heritage mountain landscape,and the reconstruction of urban landscape space The optimization of spatial layout and improvement of living environment provide possible paths;Finally,seven types of influencing factors were selected from three aspects: natural environment,socio-economic,and infrastructure.Pearson correlation and geographic detectors were used for comprehensive analysis,aiming to clarify the explanatory power of different influencing factors on urban horizontal plane(spatial distribution of building density)and vertical space(spatial distribution of building facades).This has certain reference significance for predicting and regulating the future development of spatial morphology in mountainous cities.The main research findings are as follows:(1)During the research period,the construction land area expanded by 2.25 times,and the urban spatial center gradually shifted towards areas with less undulating terrain in the south.Urban expansion was mainly characterized by enclave expansion,irregular expansion in multiple directions,and complex boundary morphology.(2)The overall compactness of the research area is relatively low,and the nuclear density shows a multi-point aggregation pattern;The calculation of 7 types of landscape pattern indices shows that the heterogeneity of building patches has increased,the spatial relationships have become more complex,the degree of fragmentation has become more severe,and the overall density has decreased while the degree of aggregation has increased;The core of the urban road axis is prominent,radiating outward from the center,and some roads have poor accessibility for traffic.(3)The overall area of the cold spot area in the research area is relatively large,with building patches mainly clustered in "low low" clusters;The overall undulation shows a gradually decreasing trend over time,with low value areas occupying a larger spatial distribution area.The dense distribution of mountains to some extent enhances the overall undulation of the research area,while the old urban area is severely densified with low undulation.;There is a large difference between the height and height of buildings.The average volume of individual buildings is significantly different.The average volume of buildings gradually rises,and the Floor area ratio drops;The results indicate that the newly proposed undulation index is suitable for characterizing the architectural and topographic undulation characteristics in mountainous urban areas,and the hot spot analysis(Getis Ord Gi *)tool evaluates the results well.(4)By combining two methods and selecting seven types of influencing factors,the main driving factors for the spatial distribution pattern and differentiation of urban building density and building height were revealed.By comparing correlation analysis and geographic exploration model detection results,it was found that the correlation coefficient and factor detection explanatory power were relatively consistent,indicating that the combination of the two methods has good applicability in the study of driving forces of urban spatial form.