Cloud Optimized GeoTIFF (COG)

Rendering a COG as a tiled layer.

Tiled data from a Cloud Optimized GeoTIFF (COG) can be rendered as a layer. In this example, a single 3-band GeoTIFF is used to render RGB data.

main.js

import 'ol/ol.css';
import GeoTIFF from 'ol/source/GeoTIFF';
import Map from 'ol/Map';
import Projection from 'ol/proj/Projection';
import TileLayer from 'ol/layer/WebGLTile';
import View from 'ol/View';
import proj4 from 'proj4';
import {getCenter} from 'ol/extent';
import {register} from 'ol/proj/proj4';

proj4.defs('EPSG:32636', '+proj=utm +zone=36 +datum=WGS84 +units=m +no_defs');
register(proj4);

const projection = new Projection({
  code: 'EPSG:32636',
  extent: [166021.44, 0.0, 534994.66, 9329005.18],
});

// metadata from https://s3.us-west-2.amazonaws.com/sentinel-cogs/sentinel-s2-l2a-cogs/2020/S2A_36QWD_20200701_0_L2A/S2A_36QWD_20200701_0_L2A.json
const sourceExtent = [499980, 1790220, 609780, 1900020];

const map = new Map({
  target: 'map',
  layers: [
    new TileLayer({
      source: new GeoTIFF({
        sources: [
          {
            url: 'https://sentinel-cogs.s3.us-west-2.amazonaws.com/sentinel-s2-l2a-cogs/2020/S2A_36QWD_20200701_0_L2A/TCI.tif',
          },
        ],
      }),
      extent: sourceExtent,
    }),
  ],
  view: new View({
    center: getCenter(sourceExtent),
    extent: sourceExtent,
    zoom: 9,
    projection: projection,
  }),
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Cloud Optimized GeoTIFF (COG)</title>
    <!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
    <script src="https://unpkg.com/elm-pep"></script>
    <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v3/polyfill.min.js?features=fetch,requestAnimationFrame,Element.prototype.classList,URL,TextDecoder,Number.isInteger"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <script src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "cog",
  "dependencies": {
    "ol": "6.6.2-dev",
    "proj4": "^2.7.5"
  },
  "devDependencies": {
    "parcel": "^2.0.0-beta.1"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --public-url . index.html"
  }
}