Advanced Mapbox Vector Tiles

mapbox 5 vector 72 tiles 6 mobile 3 grid 8

本示例演示使用自定义的瓦片 grid 加载渲染 mapbox 矢量瓦片.

一种矢量瓦片地图，为后续缩放级别复用矢量瓦片资源，以节约手机端的带宽。
注意：当mapbox的token过期后，地图会不显示。

PS：没使用过此功能，直翻的！

main.js

import MVT from 'ol/format/MVT.js';
import Map from 'ol/Map.js';
import TileGrid from 'ol/tilegrid/TileGrid.js';
import VectorTileLayer from 'ol/layer/VectorTile.js';
import VectorTileSource from 'ol/source/VectorTile.js';
import View from 'ol/View.js';
import {Fill, Icon, Stroke, Style, Text} from 'ol/style.js';
import {get as getProjection} from 'ol/proj.js';

const key =
  'Your Mapbox access token from https://mapbox.com/ here';

// Calculation of resolutions that match zoom levels 1, 3, 5, 7, 9, 11, 13, 15.
const resolutions = [];
for (let i = 0; i <= 8; ++i) {
  resolutions.push(156543.03392804097 / Math.pow(2, i * 2));
}
// Calculation of tile urls for zoom levels 1, 3, 5, 7, 9, 11, 13, 15.
function tileUrlFunction(tileCoord) {
  return (
    'https://{a-d}.tiles.mapbox.com/v4/mapbox.mapbox-streets-v6/' +
    '{z}/{x}/{y}.vector.pbf?access_token=' +
    key
  )
    .replace('{z}', String(tileCoord[0] * 2 - 1))
    .replace('{x}', String(tileCoord[1]))
    .replace('{y}', String(tileCoord[2]))
    .replace(
      '{a-d}',
      'abcd'.substr(((tileCoord[1] << tileCoord[0]) + tileCoord[2]) % 4, 1)
    );
}

const map = new Map({
  layers: [
    new VectorTileLayer({
      source: new VectorTileSource({
        attributions:
          '© <a href="https://www.mapbox.com/map-feedback/">Mapbox</a> ' +
          '© <a href="https://www.openstreetmap.org/copyright">' +
          'OpenStreetMap contributors</a>',
        format: new MVT(),
        tileGrid: new TileGrid({
          extent: getProjection('EPSG:3857').getExtent(),
          resolutions: resolutions,
          tileSize: 512,
        }),
        tileUrlFunction: tileUrlFunction,
      }),
      style: createMapboxStreetsV6Style(Style, Fill, Stroke, Icon, Text),
    }),
  ],
  target: 'map',
  view: new View({
    center: [0, 0],
    minZoom: 1,
    zoom: 2,
  }),
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Advanced Mapbox Vector Tiles</title>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <style>
      .map {
        width: 100%;
        height: 400px;
      }
      .map {
        background: #f8f4f0;
      }
    </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 src="https://openlayers.org/en/v7.3.0/examples/resources/mapbox-streets-v6-style.js"></script>
    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "mapbox-vector-tiles-advanced",
  "dependencies": {
    "ol": "7.3.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}