arcgis featureLayer的替代方案？

1 回答

• 1

  使用featurelayers可以直接在客户端上使用几何图形 . 在某些情况下，在客户端上具有几何图形是必需的（例如，如果您需要编辑功能），但在许多其他情况下，它不是更好的选择 .

  为了实现您的目标，您可以使用许多ArcGISDynamicMapServiceLayer并识别或查询任务以从服务器获取信息 .

  编辑：我修改了你发布的样本

  var map;
    require([
      "esri/map", "esri/layers/ArcGISDynamicMapServiceLayer",
      "esri/tasks/query", "esri/geometry/Circle",
      "esri/graphic", "esri/InfoTemplate", "esri/symbols/SimpleMarkerSymbol",
      "esri/symbols/SimpleLineSymbol", "esri/symbols/SimpleFillSymbol", "esri/renderers/SimpleRenderer",
      "esri/config", "esri/Color", "dojo/dom","esri/tasks/QueryTask", "dojo/domReady!"
    ], function(
      Map, ArcGISDynamicMapServiceLayer,
      Query, Circle,
      Graphic, InfoTemplate, SimpleMarkerSymbol,
      SimpleLineSymbol, SimpleFillSymbol, SimpleRenderer,
      esriConfig, Color, dom, QueryTask
    ) {
  
      esriConfig.defaults.io.proxyUrl = "/proxy/";
  
      map = new Map("mapDiv", { 
        basemap: "streets",
        center: [-95.249, 38.954],
        zoom: 14,
        slider: false
      });
  
  
      var dynamicMapServiceLayer = new ArcGISDynamicMapServiceLayer("http://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer");
  
  
      var queryTask = new QueryTask("http://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/0");
  
  
  
      var circleSymb = new SimpleFillSymbol(
        SimpleFillSymbol.STYLE_NULL,
        new SimpleLineSymbol(
          SimpleLineSymbol.STYLE_SHORTDASHDOTDOT,
          new Color([105, 105, 105]),
          2
        ), new Color([255, 255, 0, 0.25])
      );
      var circle;
  
      var symbol = new SimpleMarkerSymbol(
              SimpleMarkerSymbol.STYLE_CIRCLE,
              12,
              new SimpleLineSymbol(
               SimpleLineSymbol.STYLE_NULL,
               new Color([247, 34, 101, 0.9]),
                   1
                  ),
                  new Color([207, 34, 171, 0.5])
      );
  
      //when the map is clicked create a buffer around the click point of the specified distance.
      map.on("click", function(evt){
        circle = new Circle({
          center: evt.mapPoint,
          geodesic: true,
          radius: 1,
          radiusUnit: "esriMiles"
        });
        map.graphics.clear();
        map.infoWindow.hide();
        var graphic = new Graphic(circle, circleSymb);
        map.graphics.add(graphic);
  
        var query = new Query();
        query.geometry = circle.getExtent();
        //use a fast bounding box query. will only go to the server if bounding box is outside of the visible map
  
        require([
          "esri/tasks/query"
        ], function (Query) {
  
            var query = new Query();
            query.spatialRelationship = Query.SPATIAL_REL_CONTAINS;
            query.geometry = circle;
            query.returnGeometry = true;
            queryTask.execute(query, function (fset1) {
                dojo.forEach(fset1.features, function (feature, i) {
  
                    console.log("feature", feature);
                    feature.setSymbol(symbol);
  
                    map.graphics.add(feature);
  
                });
            });
        });
      });
  
      function selectInBuffer(response){
        var feature;
        var features = response.features;
        var inBuffer = [];
        //filter out features that are not actually in buffer, since we got all points in the buffer's bounding box
        for (var i = 0; i < features.length; i++) {
          feature = features[i];
          if(circle.contains(feature.geometry)){
            inBuffer.push(feature.attributes[featureLayer.objectIdField]);
          }
        }
        var query = new Query();
        query.objectIds = inBuffer;
        //use a fast objectIds selection query (should not need to go to the server)
        featureLayer.selectFeatures(query, FeatureLayer.SELECTION_NEW, function(results){
          var totalPopulation = sumPopulation(results);
          var r = "";
          r = "<b>The total Census Block population within the buffer is <i>" + totalPopulation + "</i>.</b>";
          dom.byId("messages").innerHTML = r;
        });
      }
  
      function sumPopulation(features) {
        var popTotal = 0;
        for (var x = 0; x < features.length; x++) {
          popTotal = popTotal + features[x].attributes["POP2000"];
        }
        return popTotal;
      }
    });
  

  回复于 2024-04-27T15:26:23+08:00