Google Earth Engine – Download Time Series Landsat 4 Images

Question

I am trying to download Landsat 4 SR data using the below code. But it is showing the error

'Line 33: Collection.toList: The value of 'count' must be positive.
Got: 0.'

Code:

var geometry = /* color: #d63000 */ee.Geometry.Polygon(
        [[[151.6174249560105, -30.397813382147582],
          [151.62892626826635, -30.417429838395567],
          [151.65579127375952, -30.411434283245875],
          [151.62885523162248, -30.39332285985209],
          [151.62233209929826, -30.39561792418842]]]);

/**
 * Function to mask clouds based on the pixel_qa band of Landsat SR data.
 * @param {ee.Image} image Input Landsat SR image
 * @return {ee.Image} Cloudmasked Landsat image
 */
var cloudMaskL457 = function(image) {
  var qa = image.select('pixel_qa');
  // If the cloud bit (5) is set and the cloud confidence (7) is high
  // or the cloud shadow bit is set (3), then it's a bad pixel.
  var cloud = qa.bitwiseAnd(1 << 5)
                  .and(qa.bitwiseAnd(1 << 7))
                  .or(qa.bitwiseAnd(1 << 3));
  // Reme edge pixels that don't occur in all bands
  var mask2 = image.mask().reduce(ee.Reducer.min());
  return image.updateMask(cloud.not()).updateMask(mask2);
};

var dataset = ee.ImageCollection('LANDSAT/LT04/C01/T2_SR')
                  .filterDate('1988-01-01', '1992-12-31')
                  .filterBounds(geometry)
                  .map(cloudMaskL457);

var l4_composite_list = dataset.toList(dataset.size());

// Number of image in the list
var n = l4_composite_list.size().getInfo();

// Find all the images less than 5% cloud cover and export to Google Drive
for (var i = 0; i < n; i++){  //put an actual angled bracket here
  var img = ee.Image(l4_composite_list.get(i));
 
  var rgb = img.select('B2','B3', 'B4').float();
  var date = img.date().format('yyyyMMdd').getInfo();
  Map.addLayer(img, {bands: ['B4', 'B3', 'B2'], min:0, max: 3000}, 'Image_'+date);

// Export to Google Drive
  Export.image.toDrive({
  image: rgb,
  description: 'L4_RGB'+ date,
  scale: 30,
  region: geometry, 
  })
}

How can I fix this?

Answer 1

your dataset is empty so there are no acquisitions of Landsat 4 of the specified region and time period available in the collection..