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TopoJSON

Demonstrates rendering of features from a TopoJSON topology.

This example uses a vector layer with ol/format/TopoJSON for rendering features from TopoJSON.

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index.html<!DOCTYPE html>
<html lang="en">
  <head>
    <title>TopoJSON</title>
    <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <script src="index.js"></script>
  </body>
</html>
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index.jsimport 'ol/ol.css';
import Map from 'ol/Map';
import View from 'ol/View';
import TopoJSON from 'ol/format/TopoJSON';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer';
import TileJSON from 'ol/source/TileJSON';
import VectorSource from 'ol/source/Vector';
import {Fill, Stroke, Style} from 'ol/style';

var key = 'pk.eyJ1IjoidHNjaGF1YiIsImEiOiJjaW5zYW5lNHkxMTNmdWttM3JyOHZtMmNtIn0.CDIBD8H-G2Gf-cPkIuWtRg';
var raster = new TileLayer({
  source: new TileJSON({
    url: 'https://api.tiles.mapbox.com/v4/mapbox.world-dark.json?secure&access_token=' + key
  })
});

var style = new Style({
  fill: new Fill({
    color: 'rgba(255, 255, 255, 0.6)'
  }),
  stroke: new Stroke({
    color: '#319FD3',
    width: 1
  })
});

var vector = new VectorLayer({
  source: new VectorSource({
    url: 'data/topojson/world-110m.json',
    format: new TopoJSON({
      // don't want to render the full world polygon (stored as 'land' layer),
      // which repeats all countries
      layers: ['countries']
    }),
    overlaps: false
  }),
  style: style
});

var map = new Map({
  layers: [raster, vector],
  target: 'map',
  view: new View({
    center: [0, 0],
    zoom: 1
  })
});
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package.json{
  "name": "topojson",
  "dependencies": {
    "ol": "6.1.1"
  },
  "devDependencies": {
    "parcel": "1.11.0"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --experimental-scope-hoisting --public-url . index.html"
  }
}