[GIS] Exporting true color sentinel image in Google Earth Engine

googlegoogle-earth-enginesentinel-2

I tried to download a sentinel image, but it seems not to work. It downloads a one band image and not 4,3,2 rgb combination as coded.

This is the code I'm using that just downloads 1 band:

var marco = /* color: #d63000 */ee.Geometry.Polygon(
    [[[-70.33198356628418, -16.667604212318242],
      [-70.33138275146484, -16.64129056542051],
      [-70.3795337677002, -16.641043857880046],
      [-70.3795337677002, -16.668426455517558]]]);


var sentinel = ee.Image('COPERNICUS/S2/20180726T144731_20180726T145459_T19KCB').select(['B4', 'B3', 'B2']);

Export.image.toDrive({
 image: sentinel,
 description: 'imageToDriveExample',
 scale: 10,
 region: marco
});

Best Answer

The code works:

The result is a multiband raster with:

Band1: band4 of S-2
Band2: band3 of S-2
Band3: band2 of S-2

Related Solutions

[GIS] Subsetting Sentinel 2 image in Google Earth Engine

What you do in EarthEngine is create a collection of Sentinel-2 images that you filter according to your criteria.

For instance if you want to limit your AOI to the map area in the code editor:

var collection = ee.ImageCollection('COPERNICUS/S2')
 .filterBounds(Map.getBounds(true))

You could also draw a polygon, name it AOI and filter to it. It might also be a good idea to filter by time:

var collection = ee.ImageCollection('COPERNICUS/S2')
 .filterBounds(AOI)
 .filterDate('2016-01-01', '2016-12-31')

Google Earth Engine – Extracting Pixel Values by Points from Multi-Band Image and Converting to Table

For a single (and big) table it's just one more piece of the mamushka:

var mapfunc = function(feat) {
  var geom = feat.geometry()
  var addProp = function(img, f) {
    var newf = ee.Feature(f)
    var date = img.date().format('yyyy-MM-dd')
    var bands = img.bandNames()
    var value = img.select(bands)
    .reduceRegion(ee.Reducer.first(), geom, 30)

    var fun = function(name, ini) {
      var ini = ee.Feature(ini)
      var val = value.get(name)
      var newname = ee.String(date).cat('-').cat(name)
      return ee.Feature(ee.Algorithms.If(val,
                        ini.set(newname, ee.String(val)),
                        ini.set(newname, ee.String('No data'))))
    }

    return ee.Feature(bands.iterate(fun, newf)) 

  }
  var newfeat = ee.Feature(glcm_sub.iterate(addProp, feat))
  return newfeat
};

and for exporting one table per band you have to make some client-side code because Export is a client-side function

var compute_band = function(bandname) {
  var mapfunc = function(feat) {
    var geom = feat.geometry()
    var addProp = function(img, f) {
      var newf = ee.Feature(f)
      var date = img.date().format('yyyy-MM-dd')
      var value = img.reduceRegion(ee.Reducer.first(), geom, 30).get(bandname)
      return ee.Feature(ee.Algorithms.If(value,
                                         newf.set(date, ee.String(value)),
                                         newf.set(date, ee.String('No data'))))
    }
    var newfeat = ee.Feature(glcm_sub.iterate(addProp, feat))
    return newfeat
  };
  return fg_points.map(mapfunc);
}

var bands = glcm_sub.bandNames().getInfo()
for (var band in bands) {
  var name = bands[band]
  var table = compute_band(name)
  // export to drive
  Export.table.toDrive(table,
  "Jam_III_2015_GLCM_16-16-"+name, //job name
  "test_GEE_export", //folder name
  "Jam_III_2015_GLCM_16-16-"+name); //file name
}

Best Answer

Related Solutions

[GIS] Subsetting Sentinel 2 image in Google Earth Engine

Google Earth Engine – Extracting Pixel Values by Points from Multi-Band Image and Converting to Table

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