1

I would like to export the NDVI with the date in the filename. Now I can only export them with a list of numbers, e.g. example NDVI_1, NDVI_2 (as in the code that I show below) ... and I want it so NDVI_18042018.

// Load a FeatureCollection 
var violada = ee.FeatureCollection("ft:1KmH70D7VKdiWocelf0RtbL_kQhGk0LGkQQ7O-ceG");

// Load a FeatureCollection Sentinel 2.
var s2 = ee.ImageCollection('COPERNICUS/S2')
      .filterBounds(violada)
      .filterDate('2016-10-01', '2017-09-30');
print(s2);

// Function to mask clouds using the Sentinel-2 QA band..
function maskS2clouds(image) {
         var qa = image.select('QA60');
 // Bits 10 and 11 are clouds and cirrus, respectively.
         var cloudBitMask = ee.Number(2).pow(10).int();
         var cirrusBitMask = ee.Number(2).pow(11).int();
 // Both flags should be set to zero, indicating clear conditions.
         var mask = qa.bitwiseAnd(cloudBitMask).eq(0).and(
         qa.bitwiseAnd(cirrusBitMask).eq(0));
// Return the masked and scaled data.
   return image.updateMask(mask).divide(10000);
}
   var imagen=s2.map(maskS2clouds);

// visualize the first image in the collection, pre- and post- mask
var visParams = {bands: ['B8','B4','B3']}
Map.addLayer(ee.Image(imagen.first()), visParams, 'clouds masked', false)
Map.addLayer(ee.Image(s2.first()), visParams, 'original', false)

//add ndwi
var addNDVI = function(image) {
  return image.addBands(image.normalizedDifference(['B8','B4']).rename('NDVI'));
};
var imagen2=imagen.map(addNDVI);
var NDVI = imagen2.select(['NDVI']);
print(ee.Image(NDVI.first()));
var composite = NDVI.qualityMosaic('NDVI').clip(violada);
print(composite);

// Visualize NDVI
var ndviPalette = ['FFFFFF', 'CE7E45', 'DF923D', 'F1B555', 'FCD163',   '99B718',
  '74A901', '66A000', '529400', '3E8601', '207401', '056201',
  '004C00', '023B01', '012E01', '011D01', '011301'];
Map.addLayer(composite.select('NDVI'),
             {min:-1, max: 1, palette: ndviPalette}, 'ndvi');
//List NDVI
var list=NDVI.toList(150);
for (var i=0;i<150;i++){
     var image=ee.Image(list.get(i));
     var name=ee.String('NDVI_')
                .cat(ee.String(ee.Number(i)))
                .getInfo();
     print(name);
// Export NDVI        
     Export.image.toDrive({ 
           image: image,
           description:name,
           scale: 10,
           region:violada,
           crs : 'EPSG:32630'
           });
}
Map.setCenter(-0.6, 42, 12);

Google earth engine code is: https://code.earthengine.google.com/7101729aaaf2f8be4a0114561b9a673e

2

From the official Documentation:

Export.image.toDrive(image, description, folder, fileNamePrefix, dimensions, region, scale, crs, crsTransform, maxPixels, shardSize, fileDimensions, skipEmptyTiles)

Creates a batch task to export an Image as a raster to Drive. Tasks can be started from the Tasks tab. "crsTransform", "scale", and "dimensions" are mutually exclusive.

Arguments: image (Image): The image to export.

description (String, optional): A human-readable name of the task. Defaults to "myExportImageTask".

folder (String, optional): The Google Drive Folder that the export will reside in.

fileNamePrefix (String, optional): The Google Drive filename for the export. Defaults to the description.*

What you want is fileNamePrefix. So:

// Load a FeatureCollection 
var violada = ee.FeatureCollection("ft:1KmH70D7VKdiWocelf0RtbL_kQhGk0LGkQQ7O-ceG");

// Load a FeatureCollection Sentinel 2.
var s2 = ee.ImageCollection('COPERNICUS/S2')
          .filterBounds(violada)
          .filterDate('2016-10-01', '2017-09-30');
print(s2);

// Function to mask clouds using the Sentinel-2 QA band..
function maskS2clouds(image) {
  // get date of the image to pass it through
  var date = image.date().millis()
  var qa = image.select('QA60');

  // Bits 10 and 11 are clouds and cirrus, respectively.
  var cloudBitMask = ee.Number(2).pow(10).int();
  var cirrusBitMask = ee.Number(2).pow(11).int();

  // Both flags should be set to zero, indicating clear conditions.
  var mask = qa.bitwiseAnd(cloudBitMask).eq(0).and(
             qa.bitwiseAnd(cirrusBitMask).eq(0));

  // Return the masked and scaled data.
  return image.updateMask(mask).divide(10000).set('system:time_start', date);
}
var imagen=s2.map(maskS2clouds);

print(ee.Image(imagen.first()))

// visualize the first image in the collection, pre- and post- mask
var visParams = {bands: ['B8','B4','B3']}
Map.addLayer(ee.Image(imagen.first()), visParams, 'clouds masked', false)
Map.addLayer(ee.Image(s2.first()), visParams, 'original', false)

//add ndwi
var addNDVI = function(image) {
  return image.addBands(image.normalizedDifference(['B8','B4']).rename('NDVI'));
};
var imagen2=imagen.map(addNDVI);

var NDVI = imagen2//.select(['NDVI']);
print(ee.Image(NDVI.first()));

var composite = NDVI.qualityMosaic('NDVI').clip(violada);
print(composite);

// Visualize NDVI
var ndviPalette = ['FFFFFF', 'CE7E45', 'DF923D', 'F1B555', 'FCD163', '99B718',
  '74A901', '66A000', '529400', '3E8601', '207401', '056201',
  '004C00', '023B01', '012E01', '011D01', '011301'];
Map.addLayer(composite.select('NDVI'),
            {min:0, max: 1, palette: ndviPalette}, 'ndvi');


//List NDVI
var list=NDVI.toList(150);
    for (var i=0;i<150;i++){
         var image=ee.Image(list.get(i));
         var date = image.date().format('yyyy-MM-dd').getInfo()
         var name= 'NDVI_'+i.toString()+'_'+date
         print(name);
    // Export NDVI        
         Export.image.toDrive({ 
               image: image,
               description: name,
               fileNamePrefix: name,
               scale: 10,
               region:violada,
               crs : 'EPSG:32630'
               });
    }
Map.setCenter(-0.6, 42, 12);
0

You may want to fiddle with the date format. And you're going to have to getInfo() on this as you've done in your example:

var s2 = ee.ImageCollection('COPERNICUS/S2');
var first = ee.Image(s2.first());
var date = first.date();
var formatted = date.format('YYYYMMdd');
  • Thanks for your response, but it's not what I'm really looking for. I need a loop so that each image or in this case when exporting NDVI gives me the date name of each one. Maybe if the answer is ok but I'm new in javascript and I have not got it – epcardiel Apr 20 '18 at 9:16

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