Wind

<!--
  示例：OpenLayers 风场流线
  要点：DataTile 提供 U/V 风场，Flow 图层用 GPU 粒子绘制流线
  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>风场流线</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:10px;align-items:center;flex-wrap:wrap;font-size:12px;color:#58606e}
  .bar label{display:flex;gap:5px;align-items:center;cursor:pointer}
  .bar select,.bar input[type=range]{font-size:12px}
  .bar .val{font-family:ui-monospace,Consolas,monospace;color:#1f5fd0;min-width:44px}
  .bar .sep{width:1px;height:16px;background:#d8dce2}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3}
</style>
</head>
<body>
<div class="bar">
  <span>页面内风场 U/V · 粒子流线</span>
  <span class="sep"></span>
  <span id="info">maxSpeed 20 m/s</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').textContent = 'OpenLayers 加载失败，请检查能否访问 cdn.jsdelivr.net';
    return;
  }


  var grid = ol.tilegrid.createXYZ({tileSize: 256, maxZoom: 10});
  var size = 256;

  var windSource = new ol.source.DataTile({
    tileGrid: grid,
    projection: 'EPSG:3857',
    transition: 0,
    wrapX: true,
    loader: function (z, x, y) {
      var extent = grid.getTileCoordExtent([z, x, y]);
      var resolution = grid.getResolution(z);
      var data = new Float32Array(size * size * 2);
      var offset = 0;
      for (var row = 0; row < size; ++row) {
        var mapY = extent[3] - (row + 0.5) * resolution;
        for (var col = 0; col < size; ++col) {
          var mapX = extent[0] + (col + 0.5) * resolution;
          var lonlat = ol.proj.toLonLat([mapX, mapY]);
          var lon = lonlat[0];
          var lat = lonlat[1];
          var u = 9 * Math.sin(lat * 0.22) + 5 * Math.cos(lon * 0.18);
          var v = 7 * Math.cos(lat * 0.16) - 5 * Math.sin(lon * 0.12);
          data[offset] = u;
          data[offset + 1] = v;
          offset += 2;
        }
      }
      return data;
    }
  });

  var map = new ol.Map({
    target: 'map',
    pixelRatio: 1,
    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'}), opacity: 0.45}),
      new ol.layer.Flow({
        source: windSource,
        maxSpeed: 20,
        particles: 4096,
        style: {
          color: [
            'interpolate',
            ['linear'],
            ['get', 'speed'],
            0, 'rgba(80, 140, 200, 0)',
            4, 'rgba(80, 180, 230, 0.75)',
            9, '#ffe082',
            14, '#fb8c00',
            20, '#e53935'
          ]
        }
      })
    ],
    view: new ol.View({
      center: ol.proj.fromLonLat([116.391, 39.907]),
      zoom: 4
    })
  });

})();
</script>
</body>
</html>