leaflet 整合 esri

此 demo 通过 proj4js 将 leaflet 与 esri 整合起来，同时添加了 ClusteredFeatureLayer 的支持。

<html>
<head>
  <meta charset=utf-8 />
  <title>Esri Leaflet Quickstart</title>
  <meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no' />

    <link rel="stylesheet" href="leaflet/leaflet.css" />
    <link rel="stylesheet" type="text/css" href="leaflet/MarkerCluster.css" />
    <script type="text/javascript" src="leaflet/leaflet-src.js"></script>
    <script type="text/javascript" src="leaflet/proj4.js"></script>
    <script type="text/javascript" src="leaflet/proj4leaflet.js"></script>
    <script type="text/javascript" src="leaflet/esri-leaflet-src.js"></script>
    <script type="text/javascript" src="leaflet/leaflet.markercluster-src.js"></script>
    <script type="text/javascript" src="leaflet/leaflet.esri.ClusteredFeatureLayer.js"></script>

  <style>
    body { margin:0; padding:0; }
    #map { position: absolute; top:0; bottom:0; right:0; left:0; }
  </style>
</head>
<body>

<div id="map"></div>

<script>
    var centerPoint = new L.LatLng(39.40, 117.30);
    var SERVICE_PATH = "http://192.168.1.111/ArcGIS/"
    // crs 的设置参考上一篇文章
    var crs = new L.Proj.CRS("EPSG:2384", "+proj=tmerc +lat_0=0 +lon_0=117 +k=1 +x_0=500000 +y_0=0 +a=6378140 +b=6356755.288157528 +units=m +no_defs",
    {
        origin: [0, 0],   
        resolutions: [
          264.583862501058,
          132.291931250529,
          66.1459656252646,
          33.0729828126323,
          16.9333672000677,
          8.46668360003387,
          4.23334180001693,
          2.11667090000847,
          1.05833545000423,
          0.529167725002117,
          0.264583862501058,
          0.132291931250529
        ] 
    });
    var mapOptions = {
        center: centerPoint,
        zoom: 0,
        crs: crs,
        attributionControl: true,
    };
    var map = L.map('map', mapOptions);
    var tileLayer = L.esri.tiledMapLayer({
      url:SERVICE_PATH + '/rest/services/[Tile 地图名称]/MapServer',
      maxZoom: 11,
      minZoom: 0,
      continuousWorld: true
    });
    map.addLayer(tileLayer);
    var featureMap = { 
      "SDE LAYER": L.esri.clusteredFeatureLayer({
        url: SERVICE_PATH + '/rest/services/[SDE 或 Feature 地图名称]/MapServer/1',
        opacity: 0.5,
        useCors: false
      })
    };
    L.control.layers(null, featureMap).addTo(map);
</script>

</body>
</html>

上一篇文章中使用了 leaflet 自身的 TileLayer 直接加载瓦片，此 demo 中通过 esri-leaflet 中的 L.esri.tiledMapLayer 加载更加方便，但是需要注意的是，以此方式必须设置 maxZoom 及 minZoom。

centerPoint 必须使用经纬度坐标，80坐标不可以呦。

使用 demo，必须替换 crs 中的投影字符串、 origin，以及地图服务的网址。

esri-leaflet 和 arcgis javascript api 的定位是不同的，更多的是用来进行数据可视化，所以对于SDE数据的维护还是使用 arcgis jsapi 更方便一些。