GeoTIFF with Overviews

使用外部鹰眼将 GeoTIFF 渲染为图层。

在一些情况下，GeoTIFF 可能有外部鹰眼。本示例使用 overviews 属性来给外部鹰眼提供 URLs。本示例从 Landsat 8 图像中，使用短波红外(B6)、近红外(B5)和可见绿色(B3)波段合成了复合材质。

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>
    <!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
    <script src="./resources/elm-pep.js"></script>
    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "cog-overviews",
  "dependencies": {
    "ol": "7.3.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}