Heatmap Weight

<!--
  示例：热力图权重
  要点：Heatmap 的 weight 函数按属性映射强度，radius / blur 可运行时调整
  依赖：OpenLayers 10.3.1 · jsDelivr CDN
-->
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta name="robots" content="noindex,follow">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>热力图权重</title>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/ol@10.3.1/ol.css">
<style>
  html,body{height:100%;margin:0}
  body{display:flex;flex-direction:column;overflow:hidden;
       font:13px/1.6 -apple-system,"Segoe UI","PingFang SC",sans-serif}
  .bar{flex:0 0 auto;padding:8px 12px;background:#f6f7f9;border-bottom:1px solid #e3e6ea;
       display:flex;gap:14px;align-items:center;font-size:12px;color:#58606e;flex-wrap:wrap}
  .bar label{display:flex;gap:6px;align-items:center}
  input[type=range]{width:110px}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3}
</style>
</head>
<body>
<div class="bar">
  <label>半径 <input type="range" id="radius" min="6" max="26" step="1" value="14"><span id="rv">14</span></label>
  <label>模糊 <input type="range" id="blur" min="4" max="30" step="1" value="18"><span id="bv">18</span></label>
  <span>点位强度取自 value 属性</span>
</div>
<div id="map"></div>
<script src="https://cdn.jsdelivr.net/npm/ol@10.3.1/dist/ol.js"></script>
<script>
(function () {
  'use strict';

  if (typeof ol === 'undefined') {
    document.getElementById('map').innerHTML =
      '<div style="padding:20px;color:#b42318">OpenLayers 加载失败，请检查能否访问 cdn.jsdelivr.net</div>';
    return;
  }

  /* 固定种子，保证每次打开分布一致 */
  var seed = 20261028;
  function rand() {
    seed = (seed * 1664525 + 1013904223) % 4294967296;
    return seed / 4294967296;
  }

  var features = [];
  for (var i = 0; i < 70; i++) {
    var lon = 116.34 + rand() * 0.12;
    var lat = 39.87 + rand() * 0.09;
    features.push(new ol.Feature({
      geometry: new ol.geom.Point(ol.proj.fromLonLat([lon, lat])),
      value: Math.round(10 + rand() * 90)
    }));
  }

  var vectorSource = new ol.source.Vector({ features: features });

  var heat = new ol.layer.Heatmap({
    source: vectorSource,
    radius: 14,
    blur: 18,
    weight: function (feature) {
      return Math.min(1, feature.get('value') / 100);
    }
  });

  new ol.Map({
    target: 'map',
    layers: [
      new ol.layer.Tile({ source: new ol.source.XYZ({url: 'https://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer/tile/{z}/{y}/{x}', attributions: 'Tiles © Esri'}) }),
      heat
    ],
    view: new ol.View({
      center: ol.proj.fromLonLat([116.40, 39.915]),
      zoom: 13
    }),
    controls: ol.control.defaults.defaults({ attribution: false })
  });

  var radiusInput = document.getElementById('radius');
  var blurInput = document.getElementById('blur');

  radiusInput.addEventListener('input', function () {
    heat.setRadius(Number(this.value));
    document.getElementById('rv').textContent = this.value;
  });

  blurInput.addEventListener('input', function () {
    heat.setBlur(Number(this.value));
    document.getElementById('bv').textContent = this.value;
  });
})();
</script>
</body>
</html>