Iterating a Landsat image collection to display as a layer in google earth engine

Question

I am working with Landsat 8/9 in Google Earth Engine (GEE) and would like some help. I have a list of Landsat images and want to do dNBR calculations to each of them and later displaying each as a layer. I get this list using variable dates so I believe it would be best to have a function where I can iterate over the list, apply the calculation and then display the scene using a designated name. I pretty new to GEE so I wanted to ask for help. I would greatly appreciate some guidance. Thank you!

I wrote code that displays images using specific numbers for example: var img1 = ee.Image(listofImages.get(0)); but this relies heavily on me editing the code to get each layer.

These image do not have the NBR calculation applied to it but I believe:

.normalizedDifference(['B5', 'B7'])

should work within a function that can iterate throughout the list as well as subtracting the scene by the prefire scene to get the dNBR by using:

var dNBR= preNBR.subtract(postNBR)

Answer 1

Here is the code how to Define a function to calculate NBR for a given Landsat image

// Function to calculate NBR
var calculateNBR = function(image) {
  var nbr = image.normalizedDifference(['B5', 'B7']).rename('NBR');
  return nbr;
};

// List of Landsat images (replace this with your list)
var listOfImages = [ee.Image('LANDSAT/LC08/C01/T1_TOA/LC08_044034_20140318'),
                    ee.Image('LANDSAT/LC08/C01/T1_TOA/LC08_044034_20150120')];

// Select pre-fire and post-fire images
var preFireImage = ee.Image(listOfImages[0]);
var postFireImage = ee.Image(listOfImages[1]);

// Calculate NBR for pre-fire and post-fire images
var preNBR = calculateNBR(preFireImage);
var postNBR = calculateNBR(postFireImage);

// Calculate dNBR
var dNBR = postNBR.subtract(preNBR).rename('dNBR');

// Display the results
Map.centerObject(postFireImage, 10);
Map.addLayer(preNBR, {min:-1, max:1, palette:['FF0000', '00FF00']}, 'Pre-fire NBR');
Map.addLayer(postNBR, {min:-1, max:1, palette:['FF0000', '00FF00']}, 'Post-fire NBR');
Map.addLayer(dNBR, {min:-1, max:1, palette:['FF0000', '00FF00']}, 'dNBR');

Make sure to replace listOfImages with your actual list of Landsat images. This code will calculate NBR for each image, then subtract the pre-fire NBR from the post-fire NBR to get dNBR, and finally display all three layers on the map.