GeoTIFF with Overviews

Rendering a GeoTIFF with external overviews as a layer.

In some cases, a GeoTIFF may have external overviews. This example uses the overviews property to provide URL for a file containing external overviews.

main.js

import GeoTIFF from 'ol/source/GeoTIFF.js';
import Map from 'ol/Map.js';
import TileLayer from 'ol/layer/WebGLTile.js';

const source = new GeoTIFF({
  sources: [
    {
      url: 'https://openlayers.org/data/raster/no-overviews.tif',
      overviews: ['https://openlayers.org/data/raster/no-overviews.tif.ovr'],
    },
  ],
});

const map = new Map({
  target: 'map',
  layers: [
    new TileLayer({
      source: source,
    }),
  ],
  view: source.getView(),
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>GeoTIFF with Overviews</title>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <style>
      .map {
        width: 100%;
        height: 400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>

    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "cog-overviews",
  "dependencies": {
    "ol": "9.1.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}