Analysis Of Urban Spatial Development Changes In Jiangxi Province Based On DMSP/OLS And NPP/VIIRS Night Light Data

At present,our country is in the rapid development stage of urbanization.The rapid expansion of urban space has caused the deterioration of the relationship between population,resources and the environment,hindering the development of the city to a higher level.Therefore,there is an urgent need to strengthen the exploration of urban issues,fully understand the law of urban space development and change,and provide support for the healthy development of urbanization.In recent years,luminous remote sensing technology has developed rapidly.Compared with conventional multi-spectral images,luminous remote sensing data has the advantages of easy acquisition,convenient processing,and large time span.Research has shown that the total amount of regional luminous light is related to the total population and economy of the region.The luminous data of long-term series can better reflect the process of regional urbanization,and it is very suitable for the dynamic monitoring and evaluation of large-scale urban spatial expansion.This article summarizes and analyzes the existing research,using the DMSP/OLS night light data in 2009 and 2011 and the NPP-VIIRS night light data in 2013,2015,2017,and 2019 as the basic data,and combined with the various data in Jiangxi Province.The statistical yearbook data corresponding to the year analyzes and explores the development process of urban space in Jiangxi Province.First,the luminous images based on two different pixel value ranges,DMSP/OLS and NPP/VIIRS,are integrated,which reduces the difference between the two types of data in the extraction of built-up areas and the total amount of luminous light.Desaturate and correct DMSP/OLS data.Through mutual correction between images and continuity correction in different years,the luminous data in the research period eliminates the phenomenon of oversaturation and has a larger pixel value range;For NPP/VIIRS data,noise reduction is performed.The 2015 NPP/VIIRS annual noise-free image is used as a mask.The luminous image during the research period is masked to denoise.Finally,the two night light data will last for a long time.The difference in sequence is minimized.Secondly,according to the characteristics of the night light data of DMSP/OLS and NPP/VIIRS,the mutation detection method and the natural discontinuity method are used to extract the urban built-up area respectively.In order to verify the accuracy of the built-up area extraction,the statistical yearbooks of various cities in Jiangxi Province are used for comparative analysis.After calculation,the total error between the built-up area extracted by this method and the built-up area range of the Jiangxi Provincial Statistical Yearbook is within2.35%;Landsat8 is used A comparative analysis of the spatial position between the image and the built-up areas of each city shows that the light data after threshold extraction is in good agreement with the built-up area distribution on the Landsat8 image.Finally,based on the built-up area extraction results of the two integrated data,this paper comprehensively analyzes the process of urban space development and changes in the cities of Jiangxi Province and the migration process of built-up areas from the aspects of scale,structure,form and landscape pattern.In the process of analyzing urban spatial development and changes,the characteristics of scale are analyzed in four aspects: luminous scale,average luminous,luminous growth,and luminous growth;the city's hierarchical structure is characterized by primacy,rank-scale rule,and Gini coefficient.Analyze in three aspects;for the migration of the city's center of gravity,the standard deviation ellipse is used to comprehensively analyze the migration process of urban built-up area expansion;for landscape pattern analysis,select the number of patches,patch density,average patch area,and patch area standards There are six landscape indexes,namely,difference,perimeter area fractal dimension,and patch aggregation index.Taking the built-up area of each city as the object,a comprehensive analysis of the change trend of the landscape pattern index in Jiangxi Province during the study period.