Merge branch 'master' of github.com:spatialthoughts/courses

code/end_to_end_gee/Supplement/Image_Collections/Landsat_Timelapse_Animation

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+var geometry = ee.Geometry.Polygon([[
+  [75.5210, 16.4779],
+  [75.5210, 16.1656],
+  [75.9906, 16.1656],
+  [75.9906, 16.4779]
+]]);
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+// Select the Landsat dataset
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+// We use "Landsat Level 2 Collection 2 Tier-1 Scenes"
+
+// Collection 2 -->
+// Landsat Collection 2 algorithm has improved
+// geometric and radiometric calibration that makes
+// the collections interoperable.
+// Learn more at https://www.usgs.gov/landsat-missions/landsat-collection-2
+
+// Level 2 -->
+// This is a surface reflectance product and 
+// have the highest level of interoperability through time.
+
+// Tier 1 -->
+// Highest quality scenes which are considered suitable
+// for time-series analysis
+var L5 = ee.ImageCollection('LANDSAT/LT05/C02/T1_L2');
+var L7 = ee.ImageCollection('LANDSAT/LE07/C02/T1_L2');
+var L8 = ee.ImageCollection('LANDSAT/LC08/C02/T1_L2');
+
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+// Data Pre-Processing and Cloud Masking
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+// Mapping of band-names to a uniform naming scheme
+var l5Bands = ['SR_B1','SR_B2','SR_B3','SR_B4','SR_B5','SR_B7'];
+var l5names = ['blue','green','red','nir','swir1','swir2'];
+
+var l7Bands = ['SR_B1','SR_B2','SR_B3','SR_B4','SR_B5','SR_B7'];
+var l7names = ['blue','green','red','nir','swir1','swir2'];
+
+var l8Bands = ['SR_B2','SR_B3','SR_B4','SR_B5','SR_B6','SR_B7'];
+var l8names = ['blue','green','red','nir','swir1','swir2'];
+
+// Cloud masking function for Landsat 4,5 and 7
+function maskL457sr(image) {
+  var qaMask = image.select('QA_PIXEL').bitwiseAnd(parseInt('11111', 2)).eq(0);
+  var saturationMask = image.select('QA_RADSAT').eq(0);
+
+  // Apply the scaling factors to the appropriate bands.
+  var opticalBands = image.select('SR_B.').multiply(0.0000275).add(-0.2);
+  var thermalBand = image.select('ST_B6').multiply(0.00341802).add(149.0);
+
+  // Replace the original bands with the scaled ones and apply the masks.
+  return image.addBands(opticalBands, null, true)
+      .addBands(thermalBand, null, true)
+      .updateMask(qaMask)
+      .updateMask(saturationMask)
+      .copyProperties(image, ['system:time_start']);
+}
+
+// Cloud masking function for Landsat 8
+function maskL8sr(image) {
+  var qaMask = image.select('QA_PIXEL').bitwiseAnd(parseInt('11111', 2)).eq(0);
+  var saturationMask = image.select('QA_RADSAT').eq(0);
+
+  // Apply the scaling factors to the appropriate bands.
+  var opticalBands = image.select('SR_B.').multiply(0.0000275).add(-0.2);
+  var thermalBands = image.select('ST_B.*').multiply(0.00341802).add(149.0);
+
+  // 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']);
+}
+
+// Apply filters, cloud-mask and rename bands
+// Filters from https://github.com/google/earthengine-catalog/blob/main/pipelines/landsat.py
+var L5 = L5
+  .filter(ee.Filter.lt('WRS_ROW', 122))  // Remove night-time images.
+  .map(maskL457sr)
+  .select(l5Bands,l5names);
+
+var L7 = L7
+  .filter(ee.Filter.lt('WRS_ROW', 122))  // Remove night-time images.
+  .filter(ee.Filter.date('1984-01-01', '2017-01-01'))  // Orbital drift after 2017.
+  .map(maskL457sr)
+  .select(l7Bands,l7names);
+
+var L8 = L8
+  .filter(ee.Filter.date('2013-05-01', '2099-01-01')) // Images before May 1 had some pointing issues.
+  .filter(ee.Filter.neq('NADIR_OFFNADIR', 'OFFNADIR'))
+  .filter(ee.Filter.lt('WRS_ROW', 122))  // Remove night-time images.
+  .map(maskL8sr)
+  .select(l8Bands,l8names);
+
+// Adjust the range depending on your 
+// application and location
+var l5Start = ee.Date.fromYMD(1985, 1, 1);
+var l5End = ee.Date.fromYMD(2001, 1, 1);
+
+var l7Start = ee.Date.fromYMD(2001, 1, 1);
+var l7End = ee.Date.fromYMD(2014, 1, 1);
+
+var l8Start = ee.Date.fromYMD(2014, 1, 1);
+var l8End = ee.Date.fromYMD(2023, 1, 1);
+
+var L5 = L5
+  .filter(ee.Filter.date(l5Start, l5End))
+  .filter(ee.Filter.bounds(geometry));
+
+var L7 = L7
+  .filter(ee.Filter.date(l7Start, l7End))
+  .filter(ee.Filter.bounds(geometry));
+
+var L8 = L8
+  .filter(ee.Filter.date(l8Start, l8End))
+  .filter(ee.Filter.bounds(geometry));
+
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+// Optional: Gap-Fill Landsat 7
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+var kernelSize = 25;
+var kernel = ee.Kernel.square(kernelSize * 30, 'meters', false);
+
+var gapFill = function(image) {
+  var start = image.date().advance(-1, 'year');
+  var end = image.date().advance(1, 'year');
+  var fill = L7.filter(ee.Filter.date(start, end)).median();
+  var regress = fill.addBands(image); 
+  var regress1 = regress.select(regress.bandNames().sort());
+  var fit = regress1.reduceNeighborhood(
+    ee.Reducer.linearFit().forEach(image.bandNames()),
+    kernel, null, false);
+  var offset = fit.select('.*_offset');
+  var scale = fit.select('.*_scale');
+  var scaled = fill.multiply(scale).add(offset);
+  return image.unmask(scaled, true);
+};
+
+// Uncomment below to do L7 Gapfilling
+// Note: Computation of gap-filling can take a long time
+// and your Export of animation may run for many hours
+
+//var L7 = L7.map(gapFill);
+
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+// Create Annual Composites
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+var merged = L5.merge(L7).merge(L8);
+
+// Select any dates from 1985 to 2023
+var years = ee.List.sequence(1995, 2010);
+
+var compositeImages = years.map(function(year) {
+  var startDate = ee.Date.fromYMD(year, 1, 1);
+  var endDate = startDate.advance(1, 'year');
+  var yearFiltered = merged.filter(ee.Filter.date(startDate, endDate));
+  var composite = yearFiltered.median();
+  return composite.set({
+    'year': year,
+    'system:time_start': startDate.millis(),
+    'system:time_end': endDate.millis(),
+  });
+});
+
+var compositeCol = ee.ImageCollection.fromImages(compositeImages);
+print('Annual Landsat Composites', compositeCol);
+
+// Select the band combination
+//var bands = ['red', 'green', 'blue'];
+var bands = ['swir1', 'nir', 'red'];
+
+// Visualize the image
+var visParams = {
+  min:0,
+  max:0.3,
+  bands: bands
+};
+
+var compositeColVis = compositeCol.map(function(image) {
+  return image
+    .visualize(visParams)
+    .clip(geometry)
+    .set('label', image.getNumber('year').format('%04d'));
+});
+
+// Earth Engine doesn't have a way to add text labels
+// Use the 3rd-party text package to add annotations
+var text = require('users/gena/packages:text');
+var scale = Map.getScale(); // This is scale for text, adjust as required
+var fontSize = 18;
+var bounds = geometry.bounds();
+var image = compositeColVis.first();
+
+var annotations = [
+  {
+    // Use 'margin' for x-position and 'offset' for y-position
+    position: 'right', offset: '5%', margin: '25%',
+    property: 'label',
+    scale: scale,
+    fontType: 'Consolas', fontSize: 18
+  }
+];
+
+var vis = {forceRgbOutput: true};
+
+// Test the parameters
+var results = text.annotateImage(image, vis, bounds, annotations);
+Map.centerObject(geometry)
+Map.addLayer(results, {}, 'Test Image with Annotation');
+
+// Apple labeling on all images
+var labeledImages = compositeColVis.map(function(image) {
+  return text.annotateImage(image, vis, bounds, annotations);
+});
+
+// Export the collection as video
+
+Export.video.toDrive({
+  collection: labeledImages,
+  description: 'Animation_with_Label',
+  folder: 'earthengine',
+  fileNamePrefix: 'animation',
+  framesPerSecond: 1,
+  dimensions: 800,
+  region: geometry,
+});
+