Research On The Temporal And Spatial Evolution Of Urban Built-up Areas In Shandong Province Based On Night Light Remote Sensing

Urban built-up area is an important area for urban construction and development,and it is the most sensitive area for urbanization.Its accurate identification is important for further research on the extension of urban boundaries to the edge in the process of urbanization,and the transformation of urban development from large-scale increments to stock improvement and improvement.Equal emphasis on incremental adjustments is important.In the past,the identification of urban built-up areas used statistical analysis methods,which had problems such as narrow application scope,low identification efficiency,and the results were greatly influenced by subjective factors.As an important product of human activities,night light can reflect the gradient changes of the urban landscape and be used to identify the scope of urban built-up areas,which is conducive to further promoting the new urbanization strategy with people as the core and guiding the future development of urban space.This paper selects Shandong Province as the research area,comprehensively considers the calibration of different types of night light data 2000 to 2019,and combines statistical data to compare the accuracy of mutation detection and K-means algorithm extraction of built-up areas;Evaluation indicators such as expansion rate,expansion strength,expansion mode,compactness index,expansion elasticity coefficient and allometric growth model are analyzed from the provincial and municipal scales based on three aspects: temporal and spatial evolution of built-up areas,spatial patterns,and economic connections and differences The evolution of urbanization expansion pattern in Shandong Province,analyzing the spatial changes and expansion characteristics of urban built-up areas.Select the main factors reflecting changes in social economy and ecological environment to study the relationship between urban built-up areas and build an index system of driving factors for built-up area expansion,and principal component analysis and regression analysis are used to determine the main driving factors;The layout characteristics and development trends of built-up areas are analyzed from two aspects.The main research conclusions are as follows:(1)The pseudo-invariant region is selected as the standard region to correct the DMSP and VIIRS data of different sensors and periods to improve the reliability of the application.Based on the K-means algorithm,the accuracy of extracting urban built-up areas in Shandong Province is relatively high,and the overall relative error rate of Shandong Province in each year is less than1.8%.The results are suitable for urban development research.(2)In the process of urbanization in Shandong Province,the province’s compactness index continued to decline from 2000 to 2019,and the layout of urban built-up areas gradually changed from central agglomeration to peripheral dispersion.The built-up areas maintained steady growth from 2000 to 2015,and entered a rapid period from 2015 to 2019.In the growth stage,the polynomial model generally shows an increasing trend.During the study period,the expansion rate of urban built-up areas in Shandong Province was higher than the urban population growth rate.The land expansion of urban built-up areas in Shandong Province was not in harmony with population growth,and the urbanization pattern gradually evolved from extensional expansion to filling and jumping expansion.During 2000-2005,2005-2010 and 2015-2019,the urban scale expansion coefficient of Shandong Province was all greater than 1.12,the built-up area showed a significant expansion trend,and the land use efficiency was low.From 2010 to 2015,the elastic coefficient of urban scale expansion in Shandong Province was less than 1.12,and the built-up area showed an obvious trend of population growth.(3)Selecting a variety of indicators to explore the driving factors of urban built-up area expansion in Shandong Province,it is found that social productivity and economic growth factors are closely related to urban expansion,among which industrial output value and resident consumption level are more prominent;population growth,science and technology education and industrial structure and other factors also has a secondary guiding role.(4)Based on the gravitational model,the spatial correlation strength of the built-up sections of each city shows that from 2000 to 2019,the spatial correlation strength of each city’s built-up sections has increased year by year,the degree of coordinated development has been enhanced,and the urban development pattern has become more and more compact,with Jinan and Qingdao as the centers.It spreads to the surrounding,presenting a multi-center spatial connection structure.Based on the Theil index decomposition method,it is found that the economic differences among the three major metropolitan areas in Shandong Province are small but there is a certain fluctuation trend.The economic differences within the metropolitan area are narrowing year by year,and the phenomenon of differentiation within each metropolitan area is obvious.Based on the deviationshare analysis method,it is found that the industrial competitiveness of the Lunan metropolitan area in Shandong Province is insufficient,the differences in the industrial structure of the provincial capital metropolitan area are scattered,and the industrial structure and competitiveness advantages of the Jiaodong metropolitan area are gradually highlighted.