In the field of Social Sciences,we often use second-hand data released by the government or research institutions.Statistical objects tend to be large scale administrative units,such as countries,provinces,etc.When studying smaller administrative units,data are often not available.Meanwhile,data are often not timeliness,and the time span is large.Croft(1978)discovered that nightlight data can be used as an indicator of human activities(Croft,1978).Recently,scientists began to use remote sensing data to estimate the data of social activities.Among them,the night lighting data released by National Oceanic and Atmospheric Administration of the United States,NOAA,is the most used.The Data was collected by the Operational Linescan System(OLS)flown by the U.S.
展开▼
