3

I've got stuck when I'm trying to calculate MNDISI with MODIS. FYI, to calculate MNDISI, that should use LST collection image and SR collection image, so I'm trying to combine MODIS Surface Reflectance (MODIS/006/MOD11A1) and MODIS LST (MODIS/006/MOD09GA).

But I've got an error with the command:

Number (Error) reduce.mean: Error in map(ID=2020_01_01): Image.select: Pattern 'LST_Day_1km' did not match any bands.

var jawa = ee.FeatureCollection("projects/ee-tugasakhirkkh/assets/Daerah_Penelitian");
Map.centerObject(jawa,7);

//Define Research Time
  var start = ee.Date('2020-01-01');
  var end = ee.Date('2020-12-31');
  
//Convert Kelvin to Celcius
  function celcius(img){
    return img.multiply(0.02).subtract(273.15)
              .copyProperties(img,['system:time_start']);
  }
//LST Terra MODIS 
  var terra_kelvin = ee.ImageCollection('MODIS/006/MOD11A1')
                       .select('LST_Day_1km')
                       .filterDate(start,end);
  var terra_LST = terra_kelvin.map(celcius);
  print(terra_LST);
  
var modisProjection = terra_LST.first().projection();
print('MODIS LST Projection:', modisProjection.nominalScale());

//Downsetting Function
function reduceres(image){
  return image.reduceResolution({
    reducer : ee.Reducer.mean(),
    maxPixels : 1024
  })
  .reproject({
    crs : modisProjection
  });
}

//MNDISI Function
function MNDISIModis(a){
  var green = a.select('sur_refl_b04'); 
  var swir = a.select('sur_refl_b05');
  var nir = a.select('sur_refl_b02');
  var b = 3;
  var lst = a.select('LST_Day_1km');
  var mndwi = (green.subtract(swir)).divide(green.add(swir)).rename('mndwi');
  var mndisi = (lst.subtract((mndwi.add(nir).add(swir)).divide(b))).divide(lst.add((mndwi.add(nir).add(swir)).divide(b))).rename('mndisi');
  return a.addBands(mndisi).copyProperties(a,['system:time_start']);
}

//MNDISI Terra
var terra_SR = ee.ImageCollection("MODIS/006/MOD09GA")
                .filterDate(start,end)
                .map(MNDISIModis)
                .map(reduceres)
                .map(function(img){
                        return img.addBands(terra_LST.filter(ee.Filter.eq('system:index',img.get('system:index'))))
                     })
    
var terraMNDISI = terra_SR.select('MNDISI').mean();
var terraMNDISI_clip = terraMNDISI.clip(jawa);

//Check the Resolution
var terra_proj = terraMNDISI_clip.projection();
print('MODIS MNDISI Projection:', terra_proj.nominalScale());

var param = {
  min: -1.0,
  max: 1.0,
  palette: [
    'FFFFFF', 'CE7E45', 'DF923D', 'F1B555', 'FCD163', '99B718', '74A901',
    '66A000', '529400', '3E8601', '207401', '056201', '004C00', '023B01',
    '012E01', '011D01', '011301'
  ],
};

Map.addLayer(terraMNDISI_clip,param,'Average MNDISI in 2020');

//Create Legend
//CreatePalette
function makeColorBarParams(palette) {
  return {
    bbox: [0, 0, 1, 0.1],
    dimensions: '200x20',
    format: 'png',
    min: 0,
    max: 1,
    palette: palette,
  };
}

//Create ColorBar
var colorBar = ui.Thumbnail({
  image: ee.Image.pixelLonLat().select(0),
  params: makeColorBarParams(param.palette),
  style: {stretch: 'vertical', margin: '0px 8px', maxHeight: '24px'},
});

//Create Panels
var legendLabels = ui.Panel({
  widgets: [
    ui.Label(param.min, {margin: '4px 5px', textAlign: 'left'}),
    ui.Label(param.max, {margin: '4px 170px', textAlign: 'right'})
  ],
  layout: ui.Panel.Layout.flow('horizontal')
});

var legendTitle = ui.Label({
  value: 'Average MNDISI in 2020',
  style: {fontWeight: 'bold'}
});

//Show Legend
var legendPanel = ui.Panel([legendTitle, colorBar, legendLabels]);
Map.add(legendPanel);

I haven't found any related reference to help solve my problem and tried with other combinations but still can't solve the problem.

Improve this question

2 Answers 2

Reset to default
3

The problem is functions order. First, you add LST band, then you compute MNDISI.

Also, this chunk won't work:

.map(function(img){
    return img.addBands(terra_LST.filter(ee.Filter.eq('system:index',img.get('system:index'))))
    })

You are mapping addBands() function trying to add bands from an ee.ImageCollection, it should be ee.Image type. No worries, .first() does the trick.

I recommend you to include addBands() in MNDISI calculation, as:

//MNDISI Function
function MNDISIModis(a){
  var green = a.select('sur_refl_b04'); 
  var swir = a.select('sur_refl_b05');
  var nir = a.select('sur_refl_b02');
  var b = 3;
  var lst = terra_LST.filter(ee.Filter.eq('system:index',a.get('system:index'))).first().select('LST_Day_1km');
  var mndwi = (green.subtract(swir)).divide(green.add(swir)).rename('mndwi');
  var mndisi = (lst.subtract((mndwi.add(nir).add(swir)).divide(b))).divide(lst.add((mndwi.add(nir).add(swir)).divide(b))).rename('mndisi');
  return a.addBands(mndisi).copyProperties(a,['system:time_start']);
}
Improve this answer
1
  • thx mate, that's work. I've made mistake with my LST equation so the result not going to pop up XD.
    – Kukuh Adi Prakoso
    Commented Dec 27, 2021 at 13:03
2

You are using the wrong collection for calculating the mean (based in your former question). It is terra_mndwi; not terra_SR. There are other errors adding bands and mapping collections. Following code fixes all issues.

var jawa = ee.FeatureCollection("projects/ee-tugasakhirkkh/assets/Daerah_Penelitian");
Map.centerObject(jawa,7);

//Define Research Time
  var start = ee.Date('2020-01-01');
  var end = ee.Date('2020-12-31');

//Time Variable
var ndays = ee.Number(end.difference(start,'day')).round();
var nmonths = ee.Number(end.difference(start,'month')).round();
var nyears = ee.Number(end.difference(start,'year')).round();
print(ndays, 'ndays');
print(nmonths, 'nmonths');
print(nyears, 'nyears');

//Convert Kelvin to Celcius
  function celcius(img){
    return img.multiply(0.02).subtract(273.15)
              .copyProperties(img,['system:time_start']);
  }
//LST Terra MODIS 
  var terra_kelvin = ee.ImageCollection('MODIS/006/MOD11A1')
                       .filterBounds(jawa)
                       .select('LST_Day_1km')
                       .filterDate(start,end);
  var terra_LST = terra_kelvin.map(celcius);
  print(terra_LST);

  var modisProjection = terra_LST.first().projection();
  print('MODIS Projection:', modisProjection.nominalScale());
  
//Downsetting Function
function reduceres(image){
  return image.reduceResolution({
    reducer : ee.Reducer.mean(),
    maxPixels : 1024
  })
  .reproject({
    crs : modisProjection
  });
}

//Define Dataset
  //Terra MODIS Surface Reflectance
    var terra_SR = ee.ImageCollection('MODIS/006/MOD09GA')
                     .filterBounds(jawa)
                     .filterDate(start,end)
                     .map(reduceres)
                     .map(function(img){
                        return img.addBands(terra_LST.filter(ee.Filter.eq('system:index',img.get('system:index'))).first())
                     })
                     
//Function Indices Terra MODIS
  var indices_terra_1 = function(a){
  //MNDWI
    var mndwi = a.expression(
                  '(Green - SWIR)/(Green + SWIR)',
                   {'Green': a.select('sur_refl_b04'),
                    'SWIR': a.select('sur_refl_b02')
                   }).rename('MNDWI');
    return a.addBands(mndwi)
            .copyProperties(a,['system:time_start']);
    };
  var terra_mndwi = terra_SR.map(indices_terra_1);
  var tst = terra_mndwi.first().projection();
  print('MNDWI Projection:', tst.nominalScale());
  //MNDISI
  var indices_terra_2 = function(aa){
    var mndisi = aa.expression(
                  '(LST - ((MNDWI + NIR + SWIR)/3))/(LST + ((MNDWI + NIR + SWIR)/3))',
                   {'LST': aa.select('LST_Day_1km'),
                    'MNDWI': aa.select('MNDWI'),
                    'NIR' : aa.select('sur_refl_b02'),
                    'SWIR': aa.select('sur_refl_b06')
                   }).rename('MNDISI');
    return aa.addBands(mndisi)
             .copyProperties(aa,['system:time_start']);
    };

var terra_mndisi = terra_mndwi.map(indices_terra_2);

print("terra_mndisi", terra_mndisi);

var tst2 = terra_mndisi.first().projection();
print('MNDISI Projection:', tst2.nominalScale());

var terraMNDISI = terra_mndisi.select('MNDISI').mean();

print("terraMNDISI", terraMNDISI);

var terraMNDISI_clip = terraMNDISI.clip(jawa);

//Check the Resolution
var terra_proj = terraMNDISI_clip.projection();
print('MODIS MNDISI Projection:', terra_proj.nominalScale());

var param = {
  min: -1.0,
  max: 1.0,
  palette: [
    'FFFFFF', 'CE7E45', 'DF923D', 'F1B555', 'FCD163', '99B718', '74A901',
    '66A000', '529400', '3E8601', '207401', '056201', '004C00', '023B01',
    '012E01', '011D01', '011301'
  ],
};

Map.addLayer(terraMNDISI_clip,param,'Average MNDISI in 2020');

//Create Legend
//CreatePalette
function makeColorBarParams(palette) {
  return {
    bbox: [0, 0, 1, 0.1],
    dimensions: '200x20',
    format: 'png',
    min: 0,
    max: 1,
    palette: palette,
  };
}

//Create ColorBar
var colorBar = ui.Thumbnail({
  image: ee.Image.pixelLonLat().select(0),
  params: makeColorBarParams(param.palette),
  style: {stretch: 'vertical', margin: '0px 8px', maxHeight: '24px'},
});

//Create Panels
var legendLabels = ui.Panel({
  widgets: [
    ui.Label(param.min, {margin: '4px 5px', textAlign: 'left'}),
    ui.Label(param.max, {margin: '4px 170px', textAlign: 'right'})
  ],
  layout: ui.Panel.Layout.flow('horizontal')
});

var legendTitle = ui.Label({
  value: 'Average MNDISI in 2020',
  style: {fontWeight: 'bold'}
});

//Show Legend
var legendPanel = ui.Panel([legendTitle, colorBar, legendLabels]);
Map.add(legendPanel);

After running it in GEE code editor, I got following result without any error.

enter image description here

Improve this answer
1
  • thx mate :D, ur answer got the same result even using my former question
    – Kukuh Adi Prakoso
    Commented Dec 27, 2021 at 13:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.