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I've been trying to export the quarterly mean surface temperature derived from Landsat-8. I stumbled upon the batch module of fitoprincipe's. However instead of exporting a single image for each quarter, it exports multiple empty images. Can someone help me figure this out?

var batch = require('users/fitoprincipe/geetools:batch');

// This example demonstrates the use of the Landsat 8 Collection 2, Level 2
// QA_PIXEL band (CFMask) to mask unwanted pixels.

function maskL8sr(image) {
  // Bit 0 - Fill
  // Bit 1 - Dilated Cloud
  // Bit 2 - Cirrus
  // Bit 3 - Cloud
  // Bit 4 - Cloud Shadow
  var qaMask = image.select('QA_PIXEL').bitwiseAnd(parseInt('11111', 2)).eq(0).copyProperties(image, ['system:time_start']);
  var saturationMask = image.select('QA_RADSAT').eq(0).copyProperties(image, ['system:time_start']);

  // Apply the scaling factors to the appropriate bands.
  var opticalBands = image.select('SR_B.').multiply(0.0000275).add(-0.2).copyProperties(image, ['system:time_start']);
  var thermalBands = image.select('ST_B.*').multiply(0.00341802).add(-124.15).copyProperties(image, ['system:time_start']);

  // Replace the original bands with the scaled ones and apply the masks.
  return image.addBands(opticalBands, null, true)
      .addBands(thermalBands, null, true)
      .updateMask(qaMask)
      .updateMask(saturationMask)
      .copyProperties(image, ['system:time_start']);
}

// Map the function over one year of data.
var collection = ee.ImageCollection('LANDSAT/LC08/C02/T1_L2')
                     .filterDate('2016-01-01', '2021-12-31')
                     .map(maskL8sr);

var composite = collection.mean();

// Display the results.
Map.setCenter(120.9854, 14.5994,10);  // Metro Manila
Map.addLayer(composite.select('ST_B10').clip(table), {min: -10, max: 50, palette: 'blue,green,yellow,orange,red'});

// // Chart time series of LST for Uganda in 2015.
// var ts1 = ui.Chart.image.series({
//   imageCollection: collection.select('ST_B10'),
//   region: table,
//   // reducer: ee.Reducer.mean(),
//   scale: 100,
//   xProperty: 'system:time_start'})
//   .setOptions({
//     title: 'LST 2015 Time Series',
//     vAxis: {title: 'LST Celsius'}});
// print(ts1);

var start = ee.Date('2016-01-01');
var end = ee.Date('2021-12-31');
var numbQuarters = end.difference(start, 'month').divide(3).ceil();

// make a composite image for every quarter
var quarterlyImages = ee.ImageCollection.fromImages(
            ee.List.sequence(1, numbQuarters).map(
              function(quarter){
              var startTemp = start.advance(
                              ee.Number(quarter).subtract(1).multiply(3), 'month');
              var endTemp = start.advance(ee.Number(quarter).multiply(3), 'month');
              var image = collection.filterDate(startTemp, endTemp)
                                    .filterBounds(table)
                                    .mean()
                                    .clip(table)
                                    .select('ST_B10');
              return image.set('system:time_start', startTemp.millis(),
                               'system:time_end', endTemp.millis());
            }));
print(quarterlyImages);


batch.Download.ImageCollection.toDrive(quarterlyImages, 'Quarterly Folder', 
                {name: 'LST_{system:index}',
                  scale: 30});

Here's the code.

2 Answers 2

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You have an error you must fix it before think to export anythings to see a correct results after export image.

enter image description here

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  • 1
    That error is from a placeholder table/geometry I imported from my assets. This can be fixed by adding this script at the top: ~~~ var table = ee.Geometry.Polygon( [[[121.18315390624996, 14.760741574087717], [121.18315390624996, 14.64252021062158], [121.3671749023437, 14.64252021062158], [121.3671749023437, 14.760741574087717]]], null, false); ~~~ Jan 4 at 11:20
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If you did it, you should run it and go to tasks and export your image like this image example to download it in your google drive or laptop.

enter image description here

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