00050_crop_type

/*
Tutorial Code by Amirhossein Ahrari
YouTube: https://www.youtube.com/@amirhosseinahrarigee

This code is part of a tutorial series on Earth Engine programming techniques
presented on the Amirhossein Ahrari YouTube channel. You are free to use and modify
this code for academic and non-academic purposes. Don't forget to subscribe to
the Amirhossein Ahrari channel and follow the videos to support the instructor!
*/

var cor = [
  [48.09532576624447,31.98308763719514],
  [48.744892416635096,31.98308763719514],
  [48.744892416635096,32.40378543571943],
  [48.09532576624447,32.40378543571943],
  [48.09532576624447,31.98308763719514]
  ]

var geometry = ee.Geometry.Polygon(cor)


Map.centerObject(geometry);


var cor2 = [48.407577810922206,32.21343415732832]

var geometry2 = ee.Geometry.Point(cor2)


var cor3 = [
  [48.505939779916346,32.19193653242509], 
  [48.63399916712338,32.1285761021755],
  [48.463024435678065,32.163749487730556], 
  [48.30874230387218,32.318129872134236]
  ]


var point3 = cor3.map(function(coor){
  return ee.Feature(ee.Geometry.Point(coor))
  })

var geometry3 = ee.FeatureCollection(point3)



var time_start = '2023', time_end = '2024'

var landsat8 = ee.ImageCollection("LANDSAT/LC08/C02/T1_L2")
.filterDate(time_start, time_end)
.filterBounds(geometry)
.map(function(img){
  var ms = img.select('SR.*')
  var gain = ee.Number(img.get('REFLECTANCE_MULT_BAND_3'))
  var offset = ee.Number(img.get('REFLECTANCE_ADD_BAND_2'))
  var sr = ms.multiply(gain).add(offset)
  var ndvi = sr.normalizedDifference(['SR_B5','SR_B4']).rename('ndvi')
  return ndvi
  .copyProperties(img, ['system:time_start', 'system:time_end','system:index'])
  })
  

var landsat9 = ee.ImageCollection("LANDSAT/LC09/C02/T1_L2")
.filterDate(time_start, time_end)
.filterBounds(geometry)
.map(function(img){
  var ms = img.select('SR.*')
  var gain = ee.Number(img.get('REFLECTANCE_MULT_BAND_3'))
  var offset = ee.Number(img.get('REFLECTANCE_ADD_BAND_2'))
  var sr = ms.multiply(gain).add(offset)
  var ndvi = sr.normalizedDifference(['SR_B5','SR_B4']).rename('ndvi')
  return ndvi
  .copyProperties(img, ['system:time_start', 'system:time_end','system:index'])
  })


var sen2 = ee.ImageCollection("COPERNICUS/S2_SR_HARMONIZED")
.filterDate(time_start, time_end)
.filterBounds(geometry)
.map(function(img){
  var ms = img.select('B.*').multiply(0.0001);
  var ndvi = ms.normalizedDifference(['B8','B4']).rename('ndvi')
  return ndvi
  .copyProperties(img, ['system:time_start', 'system:time_end','system:index'])
  })

var ndvi_collection = landsat8.merge(landsat9).merge(sen2)
.sort('system:time_start')

var month_list = ee.List.sequence(1, 12);

var monthly_ndvi = ee.ImageCollection(month_list.map(function(month){
  var month_img = ndvi_collection.filter(ee.Filter.calendarRange(month, month, 'month')).median()
  var date = ee.Date.fromYMD(2023, month, 1)
  return month_img
  .set('system:time_start', date.millis())
  .set('system:index', date.format('YYYY-MM'))
  }));

Map.addLayer(monthly_ndvi.toBands().clip(geometry),[],'ndvi',false)

var chart1 = ui.Chart.image.series(monthly_ndvi, geometry2, ee.Reducer.first(), 30, 'system:time_start')

print(chart1)

var chart2 = ui.Chart.image.seriesByRegion(monthly_ndvi,
geometry3, ee.Reducer.first(), 'ndvi', 30, 'system:time_start', 'system:index')


print(chart2)