Geographic

<!--
  说明：地理坐标显示
  核心逻辑：Graticule 画经纬网，MousePosition 用 EPSG:4326 输出指针经纬度
  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>地理坐标显示</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:12px;align-items:center;font-size:12px;color:#58606e;flex-wrap:wrap}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3}
  .ol-mouse-position{font-family:Consolas,Menlo,monospace;font-size:12px}
</style>
</head>
<body>
<div class="bar">
  <label><input type="checkbox" id="grat" checked> 经纬网</label>
  <span>鼠标位置按 EPSG:4326 输出</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;
  }

  var fromLonLat = ol.proj.fromLonLat;

  var graticule = new ol.control.Graticule({
    strokeStyle: new ol.style.Stroke({ color: 'rgba(31,95,208,0.55)', width: 1, lineDash: [4, 4] }),
    showLabels: true
  });

  var mouse = new ol.control.MousePosition({
    projection: 'EPSG:4326',
    coordinateFormat: function (c) {
      return c[0].toFixed(4) + ', ' + c[1].toFixed(4);
    }
  });

  var view = new ol.View({ center: fromLonLat([116.391, 39.907]), zoom: 6, minZoom: 2, maxZoom: 19 });

  var map = 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'}) })],
    view: view,
    controls: ol.control.defaults.defaults({ attribution: false, rotate: false }).extend([graticule, mouse])
  });

  document.getElementById('grat').addEventListener('change', function () {
    if (this.checked) {
      map.addControl(graticule);
    } else {
      map.removeControl(graticule);
    }
  });
})();
</script>
</body>
</html>