Sentinel-2 L2A Quarterly Cloudless Mosaic - True Color

//VERSION=3
function setup() {
    return {
        input: ["B04", "B03", "B02", "dataMask"],
        output: { bands: 4 }
    };
}

// Contrast enhance / highlight compress

const maxR = 3.0; // max reflectance
const midR = 0.13;
const sat = 1.2;
const gamma = 1.8;
const scalefac = 10000;

function evaluatePixel(smp) {
    const rgbLin = satEnh(sAdj(smp.B04 / scalefac), sAdj(smp.B03 / scalefac), sAdj(smp.B02 / scalefac));
    return [sRGB(rgbLin[0]), sRGB(rgbLin[1]), sRGB(rgbLin[2]), smp.dataMask];
}

function sAdj(a) {
    return adjGamma(adj(a, midR, 1, maxR));
}

const gOff = 0.01;
const gOffPow = Math.pow(gOff, gamma);
const gOffRange = Math.pow(1 + gOff, gamma) - gOffPow;

function adjGamma(b) {
    return (Math.pow((b + gOff), gamma) - gOffPow) / gOffRange;
}

// Saturation enhancement
function satEnh(r, g, b) {
    const avgS = (r + g + b) / 3.0 * (1 - sat);
    return [clip(avgS + r * sat), clip(avgS + g * sat), clip(avgS + b * sat)];
}

function clip(s) {
    return s < 0 ? 0 : s > 1 ? 1 : s;
}

//contrast enhancement with highlight compression
function adj(a, tx, ty, maxC) {
    var ar = clip(a / maxC, 0, 1);
    return ar * (ar * (tx / maxC + ty - 1) - ty) / (ar * (2 * tx / maxC - 1) - tx / maxC);
}

const sRGB = (c) => c <= 0.0031308 ? (12.92 * c) : (1.055 * Math.pow(c, 0.41666666666) - 0.055);

Evaluate and Visualize

Collection Access

Sentinel-2 L2A Quarterly Cloudless Mosaic is one of the Sentinel-2 products, that is offered in Copernicus Data Space Ecosystem. The data is accessible via Copernicus Browser. To access the data, you need a Copernicus Data Space Ecosystem account, and then either create a Sentinel Hub Process API request to the collection or to visualise the data via Copernicus Browser. The collection ID is 5460de54-082e-473a-b6ea-d5cbe3c17cca, and the collection type is byoc-5460de54-082e-473a-b6ea-d5cbe3c17cca.

General description

A true color composite uses visible light bands red, green and blue in the corresponding red, green and blue color channels, resulting in a natural colored product, that is a good representation of the Earth as humans would see it naturally. For Sentinel-2 L2A Quarterly Cloudless Mosaic, the contrast enhancement with highlight compression and the saturation enhencement were applied for better visualisation.

Description of representative images

True Color visualization of Iceland, 01.10.2023.

Quarterly Cloudless Mosaic True Color