script.js

// Sentinel-3 data Visualization V1.0.0
// Twitter: Pierre Markuse (@pierre_markuse)
// Website: https://pierre-markuse.net/
// CC BY 4.0 International - https://creativecommons.org/licenses/by/4.0/
function stretch(val, min, max) {return (val - min) / (max - min);}
function blend(bArr1, bArr2, opa1, opa2) {
    return bArr1.map(function(num, index) {
        return (num / 100 * opa1 + bArr2[index] / 100 * opa2);
    });
}

var NaturalColors1 = [1.0 * B07 + 1.4 * B09 - 0.1 * B14, 1.1 * B05 + 1.4 * B06 - 0.2 * B14, (2.6 * B04 - B14 * 0.6)*1.00];
var NaturalColors2 = [1.0 * B07 + 1.4 * B09 - 0.2 * B14, 1.0 * B05 + 1.5 * B06 - 0.45 * B14, (2.6 * B04 - B14 * 1.0)*1.02];
var NaturalColors3 = [1.0 * B07 + 1.4 * B09 - 0.3 * B14, 1.0 * B05 + 1.5 * B06 - 0.6 * B14, (2.6 * B04 - B14 * 1.2)*1.03];
var NIR = [2.0 * B14, 2.0 * B07, 2.0 * B04];
var AC = [2 * B14, 2 * B14, 2 * B14];

var layer1 = NaturalColors1; // Visualization layer 1
var layer2 = NIR; // Visualization layer 2
var layer1Amount = 100; // Amount layer 1
var layer2Amount = 0; // Amount layer 2
var stretchMin = 0.15; //Change black point
var stretchMax = 0.80; //Change white point
var saturation = 0.00; //Change saturation in percent
var brightness = 1.50; //Brightness, default=1.5
var manualCorrection = [0.00, 0.00,0.00]; //Manual correction of RGB values

var visualization = blend(layer1, layer2, layer1Amount, layer2Amount);
var result = [visualization[0] * brightness, visualization[1] * brightness, visualization[2] * brightness];
result = [stretch(result[0],stretchMin,stretchMax)+manualCorrection[0],stretch(result[1],stretchMin,stretchMax)+manualCorrection[1],stretch(result[2],stretchMin,stretchMax)+manualCorrection[2]];
var avg = (result[0]+result[1]+result[2])/3;
saturation = saturation * (-1);
if (result[0]>avg) { result[0]=result[0]-(result[0]-avg)/100*saturation } else {result[0]=result[0]+(avg-result[0])/100*saturation};
if (result[1]>avg) { result[1]=result[1]-(result[1]-avg)/100*saturation } else {result[1]=result[1]+(avg-result[1])/100*saturation};
if (result[2]>avg) { result[2]=result[2]-(result[2]-avg)/100*saturation } else {result[2]=result[2]+(avg-result[2])/100*saturation};

return result;