原文链接及内容

原文链接：https://openlayers.org/en/latest/examples/reprojection-image.html

运行界面

这个例子展示了在客户端单个图像数据源的重投影。

main.js代码如下：

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import Map from 'ol/Map.js';
import OSM from 'ol/source/OSM.js';
import Static from 'ol/source/ImageStatic.js';
import View from 'ol/View.js';
import proj4 from 'proj4';
import {Image as ImageLayer, Tile as TileLayer} from 'ol/layer.js';
import {getCenter} from 'ol/extent.js';
import {register} from 'ol/proj/proj4.js';
import {transform} from 'ol/proj.js';

proj4.defs(
  'EPSG:27700',
  '+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 ' +
    '+x_0=400000 +y_0=-100000 +ellps=airy ' +
    '+towgs84=446.448,-125.157,542.06,0.15,0.247,0.842,-20.489 ' +
    '+units=m +no_defs'
);
register(proj4);

const imageExtent = [0, 0, 700000, 1300000];
const imageLayer = new ImageLayer();

const map = new Map({
  layers: [
    new TileLayer({
      source: new OSM(),
    }),
    imageLayer,
  ],
  target: 'map',
  view: new View({
    center: transform(getCenter(imageExtent), 'EPSG:27700', 'EPSG:3857'),
    zoom: 4,
  }),
});

const interpolate = document.getElementById('interpolate');

function setSource() {
  const source = new Static({
    url:
      'https://upload.wikimedia.org/wikipedia/commons/thumb/1/18/' +
      'British_National_Grid.svg/2000px-British_National_Grid.svg.png',
    crossOrigin: '',
    projection: 'EPSG:27700',
    imageExtent: imageExtent,
    interpolate: interpolate.checked,
  });
  imageLayer.setSource(source);
}
setSource();

interpolate.addEventListener('change', setSource);

界面布局文件index.html代码如下：

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<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Image Reprojection</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>
    <div>
      <input type="checkbox" id="interpolate" checked />
      <label for="interpolate">Interpolate</label>
    </div>
    <!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
    <script src="https://cdn.jsdelivr.net/npm/elm-pep@1.0.6/dist/elm-pep.js"></script>
    <script type="module" src="main.js"></script>
  </body>
</html>