added kndvi to ndwi mosaic script

Author: azlinszkysinergise

sentinel2-quarterly-cloudless-mosaic/ndwi/script.js

@@ -1,31 +1,50 @@
 //VERSION=3
-
-function setup() {
-    return {
-        input: ["B03", "B08", "dataMask"],
-        output: { bands: 4 }
-    };
-}
-
-
+//ndwi with kndvi
 const colorRamp1 = [
-    [0, 0xFFFFFF],
-    [1, 0x008000]
+    [0, 0xFFFFFF], //Black
+    [0.7, 0x008000] //Green (lower if you want a greener map)
 ];
 const colorRamp2 = [
-    [0, 0xFFFFFF],
-    [1, 0x0000CC]
+    [0, 0xFFFFFF], //Black
+    [1, 0x0000CC]  //Medium Blue
 ];
 
-const viz1 = new ColorRampVisualizer(colorRamp1);
-const viz2 = new ColorRampVisualizer(colorRamp2);
+let viz1 = new ColorRampVisualizer(colorRamp1);
+let viz2 = new ColorRampVisualizer(colorRamp2);
+
+function setup() {
+return {
+  input: ["B03", "B04", "B08","dataMask"],
+  output: [
+      { id:"default", bands: 4 },
+      { id: "index", bands: 1, sampleType: "FLOAT32" },
+      { id: "eobrowserStats", bands: 1, sampleType: 'FLOAT32' },
+      { id: "dataMask", bands: 1 }
+  ]
+};
+}
 
 function evaluatePixel(samples) {
-    let val = index(samples.B03, samples.B08);
-    if (val < 0) {
-        imgVals = viz1.process(-val)
-    } else {
-        imgVals = viz2.process(Math.sqrt(Math.sqrt(val)))
-    }
-    return imgVals.concat(samples.dataMask);
+let factor = 1/2000;
+let Green = factor * samples.B03;
+let Red = factor * samples.B04;
+let NIR = factor * samples.B08;
+let val = index(Green, NIR);
+let kndvi = Math.tanh(Math.pow(((NIR - Red) / (NIR + Red)), 2)); //https://doi.org/10.1126/sciadv.abc7447
+let imgVals = null;
+// The library for tiffs works well only if there is only one channel returned.
+// So we encode the "no data" as NaN here and ignore NaNs on frontend.
+const indexVal = samples.dataMask === 1 ? val : NaN;
+
+if (val < -0) {
+  imgVals = [...viz1.process(kndvi), samples.dataMask];
+} else {
+  imgVals = [...viz2.process(Math.sqrt(Math.sqrt(val))), samples.dataMask];
 }
+return {
+  default: imgVals,
+  index: [indexVal],
+  eobrowserStats:[val],
+  dataMask: [samples.dataMask]
+};
+}