Single Image WMS

Example of a single image WMS layer.

WMS can be used as an Image layer, as shown here, or as a Tile layer, as shown in the Tiled WMS example. Tiles can be cached, so the browser will not re-fetch data for areas that were viewed already. But there may be problems with repeated labels for WMS servers that are not aware of tiles, in which case single image WMS will produce better cartography.

main.js

import Map from 'ol/Map.js';
import View from 'ol/View.js';
import ImageLayer from 'ol/layer/Image.js';
import TileLayer from 'ol/layer/Tile.js';
import ImageWMS from 'ol/source/ImageWMS.js';
import OSM from 'ol/source/OSM.js';

const layers = [
  new TileLayer({
    source: new OSM(),
  }),
  new ImageLayer({
    extent: [-13884991, 2870341, -7455066, 6338219],
    source: new ImageWMS({
      url: 'https://ahocevar.com/geoserver/wms',
      params: {'LAYERS': 'topp:states'},
      ratio: 1,
      serverType: 'geoserver',
    }),
  }),
];
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>Single Image 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>

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

package.json

{
  "name": "wms-image",
  "dependencies": {
    "ol": "10.4.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}