maptalks - 增大空间参考的maxZoom

增大空间参考的maxZoom
index.html
<!DOCTYPE html>
<html>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>瓦片图层与地理投影 - 增大空间参考的maxZoom</title>
  <style type="text/css">
    html,body{margin:0px;height:100%;width:100%}
    .container{width:100%;height:100%}
  </style>
  <link rel="stylesheet" href="https://unpkg.com/maptalks/dist/maptalks.css">
  <script type="text/javascript" src="https://unpkg.com/maptalks/dist/maptalks.min.js"></script>
  <body>
    <div id="map" class="container"></div>

    <script>
      var center = [105.08052356963802, 36.04231948670001];

      // set maxNativeZoom to 24
      var MAX_ZOOM = 25;
      var spatialReference = {
        'projection': 'EPSG:3857',
        'resolutions': (function () {
            const resolutions = [];
            const d = 2 * 6378137 * Math.PI;
            for (let i = 0; i < MAX_ZOOM; i++) {
                resolutions[i] = d / (256 * Math.pow(2, i));
            }
            return resolutions;
        })(),
      };

      var map = new maptalks.Map('map', {
        center: center,
        spatialReference,
        zoom: 4,
        baseLayer: new maptalks.TileLayer('base', {
          maxAvailableZoom: 22,
          urlTemplate: 'https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}.png',
          subdomains: ['a','b','c','d'],
          attribution: '&copy; <a href="http://osm.org">OpenStreetMap</a> contributors, &copy; <a href="https://carto.com/">CARTO</a>'
        })
      });

    </script>
  </body>
</html>