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I am trying to generate a chart and I am finding it hard to generate it. Is it a coding error in calling my functions? https://code.earthengine.google.com/?scriptPath=users%2Fmpalasimbarashe%2FProject1%3ABOA7Research

/// IMPORTING THE FEATURE COLLECTION ///
var points = points.map(function(feature){
  var sample_id = feature.get('Sample_ID');
  return ee.Feature(feature.geometry(), {'id': feature.id()})
    .set('Sample_ID', sample_id);
});

Map.addLayer(points,{color:'green'},'Root Locations');
Map.centerObject(points,10);
print(points);

var points_list = points.toList(points.size());

var keys = points_list.map(function (ele) {

  return ee.Feature(ele).get('id');
  
});

var values = points_list.map(function (ele) {

  return ee.Feature(ele).get('Sample_ID');
  
});

var dict = ee.Dictionary.fromLists(keys, values);

/// FILTERING THE SENTINEL IMAGE COLLECTION ////
var start_date = '2010-09-01';
var end_date   = '2011-05-30';

var criteria = ee.Filter.and(
    ee.Filter.bounds(points), ee.Filter.date(start_date, end_date));
var cloud_perc = 10;//Max cloud percentile per scene.    


var L7_col = ee.ImageCollection('LANDSAT/LE07/C01/T1_TOA')
                .filter(criteria)
                .filter(ee.Filter.lt('CLOUD_COVER', cloud_perc));


// - Import the SIAC atmospheric correction module
var siac = require('users/marcyinfeng/utils:SIAC');

// - Apply SIAC and retrieve bottom of atmosphere (BOA) reflectance
var L7_boa = siac.get_l7_sur(L7_col.first());
// var L8_boa = siac.get_l8_sur(L8_col.first()); 
// var S2_boa = siac.get_sur(S2_col.first()); 


// - Check and visualization
var Color_comp_01 = {bands:"B3,B2,B1", min: 0.0, max: 0.2, gamma: 1};
var Color_comp =    {bands:"B3,B2,B1", min:200, max:2000, gamma: 1};
Map.addLayer(L7_col.first(), Color_comp, 'TOA');
Map.addLayer(L7_boa, Color_comp_01, 'BOA');
Map.centerObject(L7_col.first())


////Adding SAIC to the Collection/// 
function siac_collection(img){

var siac = require('users/marcyinfeng/utils:SIAC');

return siac.get_sur(img).copyProperties(img,['system:time_start','system:time_end']);
}

var correctedCollection = L7_col.map(siac_collection)
    



///// KNDVI FUNCTION //////

var addKNDVI = function(correctedCollection){
  
  var RED = image.select('B4');
  var NIR = image.select('B8');
  
  /// COMPUTE D2 A RENAME TO d2 ///
  var D2 = NIR.subtract(RED).pow(2)
    .select([0],['d2']);
 
  /// GAMMA DEFINED AS 1/sigma^2
  var gamma = ee.Number(4e6).multiply(-2.0);

/// COMPUTE KERNEL (k) AND KNDVI ///

  var k = D2.divide(gamma).exp();
  var kndvi = ee.Image.constant(1)
    .subtract(k).divide(ee.Image.constant(1).add(k))
    .select([0],['kndvi']).clip(points);
    
     return image.addBands(ee.Image([kndvi]));
 
};

var testPoint = ee.Feature(points.first());
print(testPoint);

/// TIMESERIES CHART FOR SINGLE LOCATION ///
var chart = ui.Chart.image.series({
    imageCollection: correctedCollection.select('kndvi'),
    region: testPoint.geometry()
    }).setOptions({
      interpolateNulls: true,
      lineWidth: 1,
      pointSize: 3,
      title: 'KNDVI over Time at a Single Location',
      vAxis: {title: 'KNDVI'},
      hAxis: {title: 'Date', format: 'YYYY-MMM', gridlines: {count: 12}}
    })
print(chart)
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1 Answer 1

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Although there are some other strange things in your code (which I modified), apparently, the main issue is related with siac utils function. I used it with an image produced in your code and it generates same error message; as it can be observed in following picture.

enter image description here

Complete code used for generating chart without any error is presented below (for 5 arbitrary points in USA because your points variable is unavailable). So, you should explore correct use of siac utils function for this same purpose. I hope this helps.

var points = /* color: #d63000 */ee.Geometry.MultiPoint(
        [[-110.405078125, 44.25361685192184],
         [-99.94609375, 45.31406722110093],
         [-110.053515625, 36.00529263111045],
         [-96.342578125, 36.92415953072664],
         [-92.73906250000002, 41.352646664873]]);

points = ee.FeatureCollection(points);

/// IMPORTING THE FEATURE COLLECTION ///
var points = points.map(function(feature){
  var sample_id = feature.get('Sample_ID');
  return ee.Feature(feature.geometry(), {'id': feature.id()})
    .set('Sample_ID', sample_id);
});

Map.addLayer(points,{color:'green'},'Root Locations');
Map.centerObject(points,10);
print(points);

var points_list = points.toList(points.size());

var keys = points_list.map(function (ele) {

  return ee.Feature(ele).get('id');
  
});

var values = points_list.map(function (ele) {

  return ee.Feature(ele).get('Sample_ID');
  
});

var dict = ee.Dictionary.fromLists(keys, values);

/// FILTERING THE SENTINEL IMAGE COLLECTION ////
var start_date = '2010-09-01';
var end_date   = '2011-05-30';

var criteria = ee.Filter.and(
    ee.Filter.bounds(points), ee.Filter.date(start_date, end_date));
var cloud_perc = 10;//Max cloud percentile per scene.    


var L7_col = ee.ImageCollection('LANDSAT/LE07/C01/T1_TOA')
                .filter(criteria)
                .filter(ee.Filter.lt('CLOUD_COVER', cloud_perc));


// - Import the SIAC atmospheric correction module
var siac = require('users/marcyinfeng/utils:SIAC');

// - Apply SIAC and retrieve bottom of atmosphere (BOA) reflectance
var L7_boa = siac.get_l7_sur(L7_col.first());
// var L8_boa = siac.get_l8_sur(L8_col.first()); 
// var S2_boa = siac.get_sur(S2_col.first()); 


// - Check and visualization
var Color_comp_01 = {bands:"B3,B2,B1", min: 0.0, max: 0.2, gamma: 1};
var Color_comp =    {bands:"B3,B2,B1", min:200, max:2000, gamma: 1};
Map.addLayer(L7_col.first(), Color_comp, 'TOA');
Map.addLayer(L7_boa, Color_comp_01, 'BOA');
Map.centerObject(L7_col.first())

var test = L7_col.first();

var siac = require('users/marcyinfeng/utils:SIAC');

print("siac", siac.get_sur(test));

////Adding SAIC to the Collection/// 
function siac_collection(img){

  var siac = require('users/marcyinfeng/utils:SIAC');

  return img//siac.get_sur(img).copyProperties(img,['system:time_start','system:time_end']);

}

var correctedCollection = L7_col.map(siac_collection);

///// KNDVI FUNCTION //////

correctedCollection = correctedCollection.map(function (image){
  
  var RED = image.select('B4');
  var NIR = image.select('B8');
  
  /// COMPUTE D2 A RENAME TO d2 ///
  var D2 = NIR.subtract(RED).pow(2)
    .select([0],['d2']);
 
  /// GAMMA DEFINED AS 1/sigma^2
  var gamma = ee.Number(4e6).multiply(-2.0);

/// COMPUTE KERNEL (k) AND KNDVI ///

  var k = D2.divide(gamma).exp();
  var kndvi = ee.Image.constant(1)
    .subtract(k).divide(ee.Image.constant(1).add(k))
    .rename('kndvi')
    .clip(points);
    
     return image.addBands(kndvi);
 
});

var testPoint = ee.Feature(points.first());
print(testPoint);

/// TIMESERIES CHART FOR SINGLE LOCATION ///
var chart = ui.Chart.image.series({
    imageCollection: correctedCollection.select('kndvi'),
    region: testPoint.geometry()
    }).setOptions({
      interpolateNulls: true,
      lineWidth: 1,
      pointSize: 3,
      title: 'KNDVI over Time at a Single Location',
      vAxis: {title: 'KNDVI'},
      hAxis: {title: 'Date', format: 'YYYY-MMM', gridlines: {count: 12}}
    })
print(chart);
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1
  • Yes, this helped, how can I add the new KNDVI band to my SIAC collection? Because when I check for the band it's not available hence the chart is showing inconsistent results.
    – Simba
    Aug 29, 2022 at 7:57

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