Tiled WMS

本示例演示加载已缓存的 WMS 图层.

WMS 可以作为瓦片图层使用，也可以作为图像图层使用，比如这个示例中 Single Image WMS example。瓦片可以缓存使用，因此浏览器将不会重新请求那些已经看过的瓦片数据。但是对于 WMS 服务来说，不会关注瓦片可能出现重复的问题，因此，这种情况下，使用单个图像 WMS 效果会更好。

main.js

import Map from 'ol/Map.js';
import OSM from 'ol/source/OSM.js';
import TileLayer from 'ol/layer/Tile.js';
import TileWMS from 'ol/source/TileWMS.js';
import View from 'ol/View.js';

const layers = [
  new TileLayer({
    source: new OSM(),
  }),
  new TileLayer({
    extent: [-13884991, 2870341, -7455066, 6338219],
    source: new TileWMS({
      url: 'https://ahocevar.com/geoserver/wms',
      params: {'LAYERS': 'topp:states', 'TILED': true},
      serverType: 'geoserver',
      // Countries have transparency, so do not fade tiles:
      transition: 0,
    }),
  }),
];
const map = new Map({
  layers: layers,
  target: 'map',
  view: new View({
    center: [-10997148, 4569099],
    zoom: 4,
  }),
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Tiled WMS</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": "wms-tiled",
  "dependencies": {
    "ol": "7.3.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}