landsat8_classification.js

var cloud_masks = require('users/fitoprincipe/geetools:cloud_masks');
var maskClouds_SR = cloud_masks.landsatSR();

var year_list = ['2014','2015','2016','2017','2018','2019','2020'];

var month_list = ['1half','2half','year_median']

/* List of areas of interest for which classfication need to be done. */


//var aoi_list =['Chandigarh','Hyderabad','Mumbai','Gurgaon','Delhi','Chennai','Bangalore','Kolkata'];
var aoi_list =['Kolkata'];


//------------------Select image for training--------------------------------------------------
var bands = ['B1','B2', 'B3', 'B4', 'B5', 'B6','B7'];

var india = ee.FeatureCollection('users/hariomahlawat/India_Boundary')
    .geometry();


var india_image_sr = ee.ImageCollection('LANDSAT/LC08/C01/T1_SR')
    .filterBounds(india)
    .filterDate('2019-01-01','2019-12-31')
    .filter(ee.Filter.lt('CLOUD_COVER',1))
    .sort('CLOUD_COVER')
    .map(maskClouds_SR)
    .select(bands)
    ;

var india_image_training_median = india_image_sr.median();
var india_image_training_min = india_image_sr.min();
var india_image_training_max = india_image_sr.max();



//------------------Training the classifier ---------------------------------------------------------------

//Loading the training dataset
var ft = ee.FeatureCollection('users/hariomahlawat/IndiaSat');


function add_normalized_bands(image){
  var ndvi = image.normalizedDifference(['B5', 'B4']).rename('NDVI'); //vegetaion index
  var ndmi = image.normalizedDifference(['B5', 'B6']).rename('NDMI'); //moisture index
  var ndwi = image.normalizedDifference(['B3', 'B6']).rename('NDWI'); //water index
  var ndbi = image.normalizedDifference(['B6', 'B5']).rename('NDBI'); //water index
  return image.addBands(ndvi).addBands(ndwi).addBands(ndbi).addBands(ndmi);
}

function add_all_bands(median_image, min_image, max_image){
  return median_image.select('B1','B2','B3','B4','B5','B6','NDVI','NDWI','NDBI','NDMI')
  .addBands(min_image.select('B1','B2','B3','B4','B5','B6','NDVI','NDMI','NDWI','NDBI'))
  .addBands(max_image.select('B1','B2','B3','B4','B5','B6','NDWI','NDVI','NDMI'));  
  

  
}

india_image_training_median = add_normalized_bands(india_image_training_median)
india_image_training_min = add_normalized_bands(india_image_training_min)
india_image_training_max = add_normalized_bands(india_image_training_max)

var india_image_training = add_all_bands(india_image_training_median,
                                          india_image_training_min,
                                          india_image_training_max);

// Training the RF model.

var new_bands = ['B1','B2', 'B3', 'B4','B5','B6','NDVI','NDBI','NDWI','NDMI',
                'B2_1', 'B3_1', 'B4_1','NDVI_1','NDBI_1','NDWI_1','NDMI_1',
                'B2_2', 'B3_2', 'B4_2','NDVI_2','NDWI_2','NDMI_2',
                ];
                
var training = india_image_training.sampleRegions(ft,['class'],30);
var trained = ee.Classifier.randomForest(100).train(training, 'class', new_bands);


//--------------Running the classifier for Area of Interest-----------------------------------------------

for (var i in aoi_list) {
var aoi_name = aoi_list[i];
  for (var j in year_list)
  {
    for (var k in month_list)
    {  
      var year = year_list[j];
      var month = month_list[k]
      var start_month = month;
      var end_month = month;
      var start_date = '01';
      var end_date= '30';
      
      if (month == '1half')
      {
        start_month = '01';
        end_date = '30';
        end_month = '06';
        
        if (year == '2020')
        {
          end_month == '05'
        }
        
      }
      else if (month == '2half')
      {
        start_month = '07';
        end_date = '31';
        end_month = '12';
      }
      
      else if (month == 'year_median')
      {
        start_month = '01';
        end_date = '31';
        end_month = '12';
        if (year == '2020')
        {
          end_month == '05'
        }
        
      }
      else
      {
        start_month = month;
        end_date = '30';
        end_month = month;
      }
      
  
    var year = year_list[j];
      
    var aoi = aoi_list[j];
    var aoi = ee.FeatureCollection('users/hariomahlawat/india_district_boundaries')
    .filter(ee.Filter.eq('Name',aoi_name));
   
    var aoi_image_sr = ee.ImageCollection('LANDSAT/LC08/C01/T1_SR')
    .filterBounds(aoi)
    .filterDate(year + '-'+ start_month +'-'+ start_date,  year + '-'+ end_month +'-'+ end_date)
    .filter(ee.Filter.lt('CLOUD_COVER',10))
    .sort('CLOUD_COVER')
    .map(maskClouds_SR)
    .select(bands)
    ;  
    
    var aoi_image_median = aoi_image_sr.median();
    var aoi_image_min = aoi_image_sr.min();
    var aoi_image_max = aoi_image_sr.max();
    
   
   
    aoi_image_median = add_normalized_bands(aoi_image_median)
    aoi_image_min = add_normalized_bands(aoi_image_min)
    aoi_image_max = add_normalized_bands(aoi_image_max)
    
    var aoi_image = add_all_bands(aoi_image_median,
                                  aoi_image_min,
                                  aoi_image_max)
   
   
    print(aoi_name + ' - ' + year);
    print(aoi_image);
    
    var input = aoi_image;
    
    input = input.clip(aoi);
    input = input.classify(trained);

    input = input.expression('LC',{'LC':input.select('classification')});
     
    var str = aoi_name.replace(/\s/g,'');	//remove spaces in the aoi name for naming the downloaded image
    var misc = '_'+month 
      
    Export.image.toDrive({
    image: input.clip(aoi),
    description: 'landsat8_'+str + '_' + year+misc,
    maxPixels: 1e9,
    scale: 30,
    folder: 'Landsat8_'+str,
    region: aoi.geometry().bounds()
    });
      
  }  
}
}