3

I export to drive an image from Google Earth Engine. Since the image is too large, it is splitted into tiles by GEE. When I visualize each tile in QGIS, I can clearly see the borders of tiles (I am adding a screenshot from QGIS). Reflectance values change between two adjacent pixels at the border.

What can be the reason for that?

tif files visualized on qgis

var dataset = ee.FeatureCollection("USDOS/LSIB_SIMPLE/2017"),
  modis = ee.ImageCollection("MODIS/006/MOD11A2");
var turkeyBorder = dataset.filter(ee.Filter.eq('country_na', 'Turkey'));

var geometry = ee.Geometry.Polygon((([
  25.664530286665162, 39.5933922181898,
  30.8533440922453, 39.5933922181898,
  30.8533440922453, 42.155646034667264,
  25.664530286665162, 42.155646034667264,
])))

var collection1 = ee.ImageCollection("COPERNICUS/S2_SR")
  .filterBounds(geometry).filterDate("2019-10-01", "2019-11-30")
  .filterMetadata('CLOUDY_PIXEL_PERCENTAGE', 'less_than', 70)

var immedian1 = ee.Image(collection1.median()).clip(turkeyBorder) //.clip(geometry5);
Map.addLayer(immedian1, {
  bands: ['B4', 'B3', 'B2'],
  min: 0,
  max: 2000
}, " immedian1");

var median1_4 = immedian1.select("B4")
Export.image.toDrive({
  image: median1_4,
  description: 'median1_4',
  folder: '2019_istanbul',
  scale: 10,
  fileDimensions: 3328,
  region: geometry,
  maxPixels: 10000000000000,
  skipEmptyTiles: true
});
1
  • Are you setting the same visualization parameters to all the tiles? You can try to set the same "style" to all the tiles in QGIS. Probably that will make the "border effect" disappear. Commented Dec 25, 2021 at 0:10

1 Answer 1

5

In GIS:

  • Set a Min Max value for one raster (Right click > Properties... > Symbology).
  • Copy The raster's style
  • Select other rasters
  • Paste the style

enter image description here

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