Research On The Method And Application Of NPP-VIIRS Nighttime Light Data Extraction Towns

In this study,DMSP/OLS and NPP-VIIRS nighttime light remote sensing data are used as the main data sources,and a method for rapid extraction of urban construction land based on NPP-VIIRS nighttime light data is proposed.Based on this method,the Chinese 1992-2020 long time nighttime light data set is constructed for DMSP/OLS and NPP-VIIRS nighttime light data.On this basis,this paper analyzes the urban areas of China from 1992 to 2020,and analyzes the changes of urban spatial pattern at different levels in China by using GIS.The spatial pattern expansion,gravity center change,expansion intensity,expansion dynamic degree and landscape pattern index were used to analyze.This paper aims to explore the accuracy of monthly superimposed NPP-VIIRS nighttime light data extraction method in urbanization research.The main conclusions are as follows:1)Compared with the traditional threshold method,the accuracy of extracting urban construction land based on monthly superimposed NPP-VIIRS nighttime light data is higher.It can clearly divide the non-construction land and the boundary between city and suburb.In addition,this method can quickly extract urban areas.Compared with the general dynamic threshold method,the extraction method is simpler and the extraction rules are more reliable,which can be used to extract large-scale urban construction land on a global scale.2)Based on the monthly superimposed NPP-VIIRS nighttime light data extraction method,the region extraction of DMSP/OLS and NPP-VIIRS nighttime light data in 2013 was carried out.The NPP-VIIRS nighttime light data based on superposition can segment the non-urban area pixels of DMSP/OLS nighttime light data,and can eliminate the low frequency NPP-VIIRS light area,and the accuracy of extracting urban area is more than 75%.3)Based on the monthly superimposed NPP-VIIRS nighttime light data extraction method,China's long nighttime light data set is analyzed.From 1992 to 2020,China's urban area has increased by 4.8 times,and the center of gravity of urban area has moved 144.5km from southeast to northwest.The results show that the speed of urban expansion in the eastern region is higher than that in the western region,and the intensity index of urban expansion in each province is polarized seriously.There is a significant difference between the eastern coastal region and the northwest region,and the distribution of the eastern coastal region is larger than that of the central region and the northwest region.The core area,perimeter area fractal dimension and aggregation index of Chinese urban agglomerations are directly proportional to the development degree of urban agglomerations.4)The application of China's long-term nighttime light data set based on monthly superimposed NPP-VIIRS nighttime light data extraction method in different levels of China's regional scale is the same as the result of actual urban area change.It shows that the method is fast and effective in the extraction of regional urbanization in China.