CLMS HR-S&I: Fractional Snow Cover - Normalised difference snow index (%) visualisation script

//VERSION=3

function setup() {
  return {
    input: ["NDSI", "dataMask"],
    output: { bands: 4, sampleType: "AUTO" },
  };
}

const ramps = [
  [0, 0xffffff],
  [100, 0x4d4dff],
];

const visualizer = new ColorRampVisualizer(ramps);

function evaluatePixel(sample) {
  var NDSI_viz = visualizer.process(sample.NDSI);
  if (sample.NDSI == 255) {
    return [0, 0, 0, sample.dataMask];
  } else if (sample.NDSI == 205) {
    return [0.9, 0.9, 0.9, sample.dataMask];
  } else {
    return [NDSI_viz[0], NDSI_viz[1], NDSI_viz[2], sample.dataMask];
  }
}

General description of the script

This script visualises Fractional Snow Cover NDSI. The product provides the NDSI values in the detected snow area, i.e. area where FSCTOC > 0%.

Description of representative images

23rd April 2020, Innsbruck, AT

Resources

• Data source