原文链接及内容

原文链接：https://openlayers.org/en/latest/examples/vector-label-decluttering.html

运行界面

这里整理标签是为了避免标签重叠。设置文本样式的overflow：true，使得没有包含在多边形边界内的标签被清理。

main.js代码如下：

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import GeoJSON from 'ol/format/GeoJSON.js';
import Map from 'ol/Map.js';
import VectorLayer from 'ol/layer/Vector.js';
import VectorSource from 'ol/source/Vector.js';
import View from 'ol/View.js';
import {Fill, Stroke, Style, Text} from 'ol/style.js';
import {fromLonLat} from 'ol/proj.js';

const map = new Map({
  target: 'map',
  view: new View({
    center: fromLonLat([-100, 38.5]),
    zoom: 4,
  }),
});

const labelStyle = new Style({
  text: new Text({
    font: '12px Calibri,sans-serif',
    overflow: true,
    fill: new Fill({
      color: '#000',
    }),
    stroke: new Stroke({
      color: '#fff',
      width: 3,
    }),
  }),
});
const countryStyle = new Style({
  fill: new Fill({
    color: 'rgba(255, 255, 255, 0.6)',
  }),
  stroke: new Stroke({
    color: '#319FD3',
    width: 1,
  }),
});
const style = [countryStyle, labelStyle];

const vectorLayer = new VectorLayer({
  background: 'white',
  source: new VectorSource({
    url: 'https://openlayers.org/data/vector/us-states.json',
    format: new GeoJSON(),
  }),
  style: function (feature) {
    const label = feature.get('name').split(' ').join('\n');
    labelStyle.getText().setText(label);
    return style;
  },
  declutter: true,
});

map.addLayer(vectorLayer);

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>Vector Label Decluttering</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="https://cdn.jsdelivr.net/npm/elm-pep@1.0.6/dist/elm-pep.js"></script>
    <script type="module" src="main.js"></script>
  </body>
</html>