script.js

//VERSION=3

// Normalized Difference Vegetation Index, NDVI
// Negative values of NDVI (values approaching -1) correspond to water. 
// Values close to zero (-0.1 to 0.1) generally correspond to barren areas of rock, sand, or snow. 
// Low, positive values represent shrub and grassland (approximately 0.2 to 0.4).
// High values indicate temperate and tropical rainforests (values approaching 1).
// Thresholds may be adapted depending on local conditions.

function setup() {
  return {
    input: ["B17", "B08"],
    output: { bands: 3 }
  };
}

function evaluatePixel(sample) {

  // Calculate NDVI
  var NDVI = index(sample.B17, sample.B08);

  // Color depending on class
  if (NDVI<-1.1) return [0,0,0];
  else if (NDVI<-0.2) return [0.75,0.75,0.75];
  else if (NDVI<-0.1) return [0.86,0.86,0.86];
  else if (NDVI<0) return [1,1,0.88];
  else if (NDVI<0.025) return [1,0.98,0.8];
  else if (NDVI<0.05) return [0.93,0.91,0.71];
  else if (NDVI<0.075) return [0.87,0.85,0.61];
  else if (NDVI<0.1) return [0.8,0.78,0.51];
  else if (NDVI<0.125) return [0.74,0.72,0.42];
  else if (NDVI<0.15) return [0.69,0.76,0.38];
  else if (NDVI<0.175) return [0.64,0.8,0.35];
  else if (NDVI<0.2) return [0.57,0.75,0.32];
  else if (NDVI<0.25) return [0.5,0.7,0.28];
  else if (NDVI<0.3) return [0.44,0.64,0.25];
  else if (NDVI<0.35) return [0.38,0.59,0.21];
  else if (NDVI<0.4) return [0.31,0.54,0.18];
  else if (NDVI<0.45) return [0.25,0.49,0.14];
  else if (NDVI<0.5) return [0.19,0.43,0.11];
  else if (NDVI<0.55) return [0.13,0.38,0.07];
  else if (NDVI<0.6) return [0.06,0.33,0.04];
  else return [0,0.27,0];