potato_yield_ndvi

/**** Start of imports. If edited, may not auto-convert in the playground. ****/
var farms = ee.FeatureCollection("users/sajalsaini09/potato_yield_final"),
    modis = ee.ImageCollection("MODIS/061/MOD13Q1"),
    visParams = {"min":0,"max":0.7,"palette":["white","green"]};
/***** End of imports. If edited, may not auto-convert in the playground. *****/
Map.addLayer(farms, {color: 'blue'}, 'Farm')
Map.centerObject(farms, 15)
var saudi = ee.FeatureCollection(farms)
var sentinel = ee.ImageCollection('COPERNICUS/S2').filter(ee.Filter.date('2016-02-02', '2016-02-28')).filterBounds(farms)
var senImage = sentinel.first()
print(senImage)
function addNDVI(image){
  var ndvi = image.expression(
    "((NIR-Red) / (NIR + Red))", {
      'NIR': image.select('B8'),
      'Red': image.select('B4')
    }).rename('ndvi');
    return image.addBands(ndvi);
}
var LC08ndvi = sentinel.map(addNDVI);
var L8ndvi = LC08ndvi.select('ndvi').mean();
var reduced = L8ndvi.reduceRegions({
  collection: saudi,
  scale: 10,
  reducer: ee.Reducer.mean()
});
print(reduced, 'NDVI Values');
var chart = ui.Chart.feature.byFeature({
  features: reduced,
  xProperty: 'Feature Index',
  yProperties: ['mean']}).setOptions({
    interpolateNulls: true,
    lineWidth: 1,
    pointSize: 3,
    title: 'NDVI over Time',
    vAxis: {title: 'NDVI Value'},
    hAxis: {title: 'Plot Number', gridlines: {count: 12}}
  })
  
print(chart)