GEE Tutorials

Google Earth Engine Tutorial: Download NBR and Visualize in ArcGIS

Credit: Youtube Channel “Terra Spatial, Learn how to download Normalized Burn Ratio images and view them in ArcGIS for burn severity assessment.”

You can see all the tutorials from here: Techgeo Academy.


NBR (Normalized Burn Ratio) Overview

The Normalized Burn Ratio (NBR) is a remote sensing index used to assess burn severity in vegetation. It leverages the near-infrared (NIR) and shortwave infrared (SWIR) bands of satellite imagery to highlight burned areas. Commonly applied to Landsat data, NBR provides insights into post-fire vegetation recovery and land degradation.

Step 1: Access Google Earth Engine

Visit the Google Earth Engine platform (https://earthengine.google.com) and sign in using a Google account. Once logged in, open the Code Editor and select a relevant dataset, such as Landsat 8 Surface Reflectance (COPERNICUS/LANDSAT/LC08/C01/T1_SR).

Step 2: Calculate NBR in Google Earth Engine

Use the following JavaScript code to calculate NBR:


var dataset = ee.ImageCollection('COPERNICUS/LANDSAT/LC08/C01/T1_SR')
  .filterDate('2020-01-01', '2020-12-31')
  .filter(ee.Filter.lt('CLOUD_COVER', 20));
var image = dataset.first();
var nir = image.select('SR_B5');
var swir = image.select('SR_B6');
varnbr = nir.subtract(swir).divide(nir.add(swir)).rename('NBR');
Map.addLayer(nbr, {min: -1, max: 1, palette: ['red', 'white', 'blue']}, 'NBR');

This code selects the NIR (band 5) and SWIR1 (band 6) bands from Landsat 8, computes the NBR, and visualizes it on the map with a color palette.

Step 3: Export the NBR Image

After calculating NBR, export the resulting image to Google Drive:


Export.image.toDrive({
  image: nbr,
  description: 'NBR_Export',
  folder: 'GEE_Exports',
  fileNamePrefix: 'NBR',
  region: image.geometry(),
  scale: 30,
  crs: 'EPSG:4326',
  maxPixels: 1e10
});

This will generate a GeoTIFF file in your Google Drive, ready for import into ArcGIS.

Step 4: Import and Visualize in ArcGIS

Open ArcGIS Pro and add the exported GeoTIFF file. Use the Raster Calculator tool (under the Spatial Analyst toolbox) to recompute the NBR if necessary. Adjust the symbology to enhance burned areas using a divergent color scheme (e.g., red for high burn severity, blue for low).

FAQ

What is NBR used for?

NBR is primarily used to measure burn severity in vegetation by comparing the reflectance of near-infrared and shortwave infrared bands. It helps in analyzing post-fire landscapes and monitoring recovery over time.

Can I use other satellite data for NBR calculations?

Yes, NBR can be calculated using other satellites like Sentinel-2 or Landsat 7, provided they include the appropriate NIR and SWIR bands. Adjust the band names in your code accordingly.

What export formats are compatible with ArcGIS?

GeoTIFF (.tiff) is the most common format supported by ArcGIS. Ensure the export settings in GEE match the required resolution and coordinate system for seamless integration.

How to handle large datasets in GEE?

For large areas, use the `region` parameter to define your study area’s geometry. Limit the `maxPixels` value to avoid export failures, or use `clip()` to focus on a specific region.


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