animation_script.js

/// define a geometry called Geometry. This script is tested on a region in south korea
/// script here https://code.earthengine.google.com/856588caf0ec3d680310d96386db71fb 
/// I acknowledge and thanks the Google Earth Engine Developers mailing list for the help with this
/// Non commerical code, purely for educational purposes
/// A summer 2018 project by Andrew Cutts

// Landat 5 surface reflection data
var L5coll = ee.ImageCollection('LANDSAT/LT05/C01/T1_SR')
.filter(ee.Filter.lt('CLOUD_COVER',25))
.select(['B3', 'B2', 'B1'])
.filterBounds(geometry)

// Landat 7 surface reflection data, fill in the gaps! See USGS pages for more info
var L7coll = ee.ImageCollection('LANDSAT/LE07/C01/T1_SR')
.filter(ee.Filter.lt('CLOUD_COVER',25))
.select(['B3', 'B2', 'B1'])
.filterBounds(geometry)
.map(function(image){
  var filled1a = image.focal_mean(2, 'square', 'pixels', 1)
  return filled1a.blend(image);
})

// Landat 8 surface reflection data, rename the band names. See USGS pages for more info
var L8coll = ee.ImageCollection('LANDSAT/LC08/C01/T1_SR')
.filter(ee.Filter.lt('CLOUD_COVER',5))
.filterBounds(geometry)
.map(function(image){
  return image.rename(['B0', 'B1', 'B2', 'B3', 'B4', 'B5', 'B6', 'B7', 'B8', 'B9', 'B10', 'B11']);
})
.select(['B3', 'B2', 'B1']);

// merge L5, L7 & L8
var collection_merge = ee.ImageCollection(L5coll.merge(L7coll.merge(L8coll)));
print (collection_merge)

// create a list of years to be iterated over next..
var years = ee.List.sequence(1984, 2018)
//print (years)

// create a collection with 1 image for each year
var collectYear = ee.ImageCollection(years
  .map(function(y) {
    var start = ee.Date.fromYMD(y, 1, 1)
    var end = start.advance(12, 'month');
    return collection_merge.filterDate(start, end).reduce(ee.Reducer.median())
    
}))

//print (collectYear)

// count number of bands in each image, if 0 remove from image collection
var nullimages = collectYear
    .map(function(image) {
      return image.set('count', image.bandNames().length())
    })
    .filter(ee.Filter.eq('count', 3))
//print(nullimages)

// visualise the collection
var finalCollection = nullimages.map(function(image){
  return image.visualize({bands: ['B3_median', 'B2_median', 'B1_median'], min: 300, max: 1800});

})

// Export the collection to video based on the geometry region
Export.video.toDrive({
  collection: finalCollection,
  description: 'yearly',
  dimensions: 1080,
  framesPerSecond: 1,
  region: geometry
});


// add to map the first image in collection to check
var median_1987 = finalCollection.first()
Map.addLayer(median_1987, {bands: ['vis-red', 'vis-green', 'vis-blue']}, 'first image7');