GDP Spatialization Research Of Sichuan Province Based On Nighttime Light Data

GDP is one of the important indicators for measuring the economic situation of a country or region,and is the core indicator of national economic accounting.Traditional GDP comes from statistical data,which can only show the macroeconomic situation of a region from a numerical perspective.However,the regional differences cannot be reflected by the traditional GDP.The spatialized density map of GDP can effectively reflect the spatial differences within the region.Sichuan is a major province of population and resource.In addition,its terrain has significant features such as complexity,diversity,large relative height difference,high in the west and low in the east.At the same time,the economic development also has significant spatial differences because of the historical,economic,political,and geographical factors in Sichuan Province.This paper selects Sichuan Province as the study region,uses correlation analysis and regression analysis combining the nighttime light data,GDP statistics and other ancillary data,to achieve the GDP spatialized simulation of long time series between 2001 and 2016.Furthermore,this paper also analyzes the temporal and spatial changes of GDP from the perspectives of time series,expansion range,growth type,elevation classification,overall and partial spatial correlation.The main conclusions are as follows:(1)Combining the GDP statistics and nighttime light data of Sichuan Province,three light indexes of average relative light intensity(I),ratio of light area to total area(S)and compounded night light index(CNLI)are constructed.According to the correlation coefficient between the light indexes and GDP,the optimum light index is determined.Based on CNLI light index,the regression model is built,and the GDP spatialization density map of Sichuan Province is simulated.(2)The GDP spatialization density map reflects the spatial differences within the Sichuan economy intuitively.The macroeconomic of Sichuan Province has a good development from 2001 to 2016.However,there are some differences in regional development.The Chengdu Plain and its surrounding regions are centralized economic development regions of Sichuan Province.The economic development of the Northwest Sichuan Plateau and Southwest Sichuan Mountain areas are relatively slow.Liangshan,Aba and Ganzi are the weak economic zones in Sichuan Province.The show that the four-year determination coefficient exceeds 0.99 according to the accuracy verification and error analysis of GDP spatialized density map and GDP statistical data in Sichuan Province,and its accuracy increases with the increase of years.(3)The GDP of Sichuan Province has significant differences in spatial and temporal variation characteristics.From 2001 to 2016,the GDP growth of Sichuan Province gradually accelerated and then tended to be flat.Between 2006 and 2011,GDP grew fastest.In the spatial development pattern,most cities with GDP greater than 10 million in Sichuan Province present a concentric circular structure of development centered on the central city,and the trend of GDP expansion toward the surrounding areas is remarkable.The number of regions with GDP greater than 10 million in Ganzi and Aba is small but increasing year by year.In terms of the type of GDP growth,from the center of the city to outward,most cities in Sichuan Province are the rapid growth type,fairly rapid growth type,medium growth type,fairly slow growth type successively.Sichuan Province has a larger proportion of regions with no significant GDP growth.(4)The vertical difference of GDP distribution in Sichuan Province is obvious.The relationship between the economic development of Sichuan Province and the elevation is close.The high GDP areas of Sichuan Province mainly distribute in the elevation range below 1000 meters above sea level.This elevation range is also the distribution area of 70% of the provincial districts and counties.There are many restrictive factors for economic development in high altitude regions,and GDP value accounts for a small proportion in the whole province.(5)As for the correlation of GDP spatial statistics,the overall economic spatial difference of Sichuan Province increases first and then decreases,and the development among districts and counties tends to be dispersed and then agglomerated.From the local perspective,the high-high agglomeration regions and hot spots of GDP mainly distribute in Chengdu,Deyang,Mianyang,Ziyang,etc,with little change from 2001 to 2016.The western Sichuan regions are the main distribution area of districts and counties with low GDP,and the districts and counties are in an independent development.