NTL_China.txt

//collecting VIIRS night-time light subset across China in 2017

//import boundary
var BD = ee.FeatureCollection("users/cyangpkucues/shp_files/CN-sheng-A");
Map.addLayer(BD);
//Map.centerObject(BD,10);
print(BD);

var dataset = ee.ImageCollection('NOAA/VIIRS/DNB/MONTHLY_V1/VCMCFG')
                  .filter(ee.Filter.date('2017-01-01', '2017-12-31'));
                  
var startDate = "2017-1-1";
var endDate = "2017-12-31";
Map.centerObject(BD,8);

var NTL = dataset.select('avg_rad')
  .filterDate(startDate, endDate)
  .filterBounds(BD);
NTL = NTL.mean().clip(BD);
//var nighttimeVis = {min: 0.0, max: 60.0};
//Map.centerObject(BD,8);
//Map.addLayer(NTL, nighttimeVis, 'Nighttime');
//Map.addLayer(NTL);

Export.image.toDrive({
  image: NTL,
  description: "NTL_avg_2017_CN",
  fileNamePrefix: "NTL_avg_2017_CN",
  scale: 750,
  region: BD,
  crs: "EPSG:4326",
  maxPixels: 1e39
});