EO Browser - Sentinel 2 indices geoTIFF Raster bands

Using EO Browser I’ve downloaded the NDVI index,
why the geotiff 32bit has 3bands and not a unique band with the NDVI value of the pixels ?
Is possibile to obtain a one band raster? Or which of the 3 bands is the correct one ?

many thanks
Simone

Hi Simone

You get 3 bands because NDVI layer in EO browser is a visualized layer therefore has RGB bands.

Yes it is possible to download only 1 band with actual NDVI values on EO browser.

Please refer to this thread for a detailed answer.

You need to first create your custom layer using this script below which returns 1 NDVI band

//VERSION=3
    function setup() {
      return{
        input: [{
          bands: ["B04", "B08"]
        }],
        output: {
          id: "default",
          bands: 
        }
      }
    }
    function evaluatePixel(sample) {
      let ndvi = (sample.B08 - sample.B04) / (sample.B08 + sample.B04)
      return [ ndvi ]
    }
  • instead of selecting NDVI, go to custom , then paste the script above to custom script section

  • When you go to download your custom layer, it should be 1 band, and you can also select geotiff 32 bit.

hope that helps, otherwise feel free to ask further questions


Thank you for your answer, but I get errors on the script.
I cannot find the error…
many thanks
Regards

Hi @meteoclima,

Sorry, there was a typo in @dorothyrono’s code: it is missing the parameter that sets the output number of bands, which in this case should be 1.

If you try the following Evalscript, it should work (see example):

//VERSION=3
function setup() {
  return {
    input: ["B08", "B04"],
    output: { bands: 1 }
  };
}

function evaluatePixel(sample) {
  var ndvi = (sample.B08 - sample.B04) / (sample.B08 + sample.B04);  
  return [ndvi];
}

Note: this script in itself is designed for display purposes (scaled to the range 0-255). However, when you select Image format: TIFF (32-bit float) in the download section of EO Browser (under Analytical) the system will retrieve the raw values in Float for you.

Hello,
thank you very much. Yes It works fine! great!

Best Regards
Simone