Google Earth Engine: how to export large image as one image not tiles

Question

I want to download sentinel5 data for no2 for Saudi Arabia the whole country. This is my code:

var collection = ee.ImageCollection('COPERNICUS/S5P/OFFL/L3_NO2')
  .select('NO2_column_number_density')
  .filterDate('2019-06-01', '2019-06-06')
  .mean()
  .clip(AOI)

var band_viz = {
  min: 0,
  max: 0.0002,
  palette: ['black', 'blue', 'purple', 'cyan', 'green', 'yellow', 'red']
};



Map.addLayer(collection, band_viz, 'S5P N02');
Map.setCenter(65.27, 24.11, 4);


Export.image.toDrive({
  image:collection,
  description:"NO22019",
  shardSize: 100,
  fileDimensions: 100,
  scale: 60,
  region: AOI,
  maxPixels:1E10,
  crs: 'EPSG:3857'
})

Is there a way I could export a single image for the whole country?

Answer 1

A few things. Your export script has shardSize and fileDimensions, which are parameters for tiled outputs. Also, your scale is set to 60 which is much finer resolution than the actual product you are mapping, which is not recommended. Changing those, and the definition of your AOI since yours was not given, leaves you with a script that exports a single image for the country. Also note that I export an RGB version that uses your visualization parameters.

var AOI = ee.FeatureCollection("USDOS/LSIB_SIMPLE/2017")
.filter(ee.Filter.eq('country_na', 'Saudi Arabia'));
print("AOI",AOI);

var collection = ee.ImageCollection('COPERNICUS/S5P/OFFL/L3_NO2')
  .select('NO2_column_number_density')
  .filterDate('2019-06-01', '2019-06-06')
  .mean()
  .clip(AOI);
print("collection",collection);

var band_viz = {
  min: 0,
  max: 0.0002,
  palette: ['black', 'blue', 'purple', 'cyan', 'green', 'yellow', 'red']
};


Map.addLayer(AOI, {}, 'AOI');
Map.addLayer(collection, band_viz, 'S5P N02');
Map.centerObject(AOI, 5);


Export.image.toDrive({
  image:collection,
  description:"NO22019",
  scale: 1113.2,
  region: AOI,
  maxPixels:1E13,
  crs: 'EPSG:3857'
});

Export.image.toDrive({
  image:collection.visualize(band_viz),
  description:"NO22019_viz",
  scale: 1113.2,
  region: AOI,
  maxPixels:1E13,
  crs: 'EPSG:3857'
});