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View Dot density with multiple classes sample in sandbox
Dot density with multiple classes

Description

Show multiple classes on using a dot density renderer.

Code

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no"/>
    <title>Dot Density Renderer - Multiple Variables</title>
    <link rel="stylesheet" href="https://js.arcgis.com/3.35/esri/css/esri.css">
    <style>
      html, body, #map {
        height: 100%;
        margin: 0;
      }
      #map {
        background-color: #000
      }
      #infopane {
        position: absolute;
        width: 300px;
        top: 0;
        right: 0;
        background-color: rgba(0,0,0,0.75);
        padding: 10px;
        border-radius: 0 0 0 10px;
        font-family: Segoe UI;
        color: #aaa;
      }
      .esriLegendServiceLabel, #info-title {
        font-weight: 600;
      }
      .hidden {
        display: none;
      }
      #toggle-button {
        cursor: pointer;
      }
    </style>
    <script src="https://js.arcgis.com/3.35/"></script>
    <script>
      var map;
      require([
        "esri/map", "esri/geometry/Extent", "esri/layers/FeatureLayer", "esri/InfoTemplate", "esri/layers/ArcGISTiledMapServiceLayer",
        "esri/renderers/SimpleRenderer", "esri/symbols/SimpleFillSymbol", "esri/symbols/SimpleLineSymbol", "esri/renderers/DotDensityRenderer", "esri/renderers/ScaleDependentRenderer",
        "esri/Color", "dojo/query", "dojo/dom", "esri/dijit/Legend", "dojo/domReady!"
      ], function(Map, Extent, FeatureLayer, InfoTemplate, ArcGISTiledMapServiceLayer, SimpleRenderer, SimpleFillSymbol, SimpleLineSymbol, DotDensityRenderer, ScaleDependentRenderer, Color, query, dom, Legend) {
        map = new Map("map", {
          center: [-122.12, 37.60],
          zoom: 10,
          maxZoom: 12,
          minZoom: 9
        });
        
        var basemap = new ArcGISTiledMapServiceLayer("https://server.arcgisonline.com/ArcGIS/rest/services/Canvas/World_Light_Gray_Base/MapServer", {
          opacity: 0.15
        });
        map.addLayer(basemap);

        var layer = new FeatureLayer("https://services.arcgis.com/V6ZHFr6zdgNZuVG0/arcgis/rest/services/BayAreaWorkingClasses/FeatureServer/0", {
          outFields: ["CC","SC","WC","FFF"]
        });
        
        var createRenderer = function(dotValue) {
          return new DotDensityRenderer({
            fields: [{
              name: "CC",
              color: new Color([21, 137, 255])
            }, {
              name: "SC",
              color: new Color([200, 111, 0])
            }, {
              name: "WC",
              color: new Color([0, 255, 0])
            }, {
              name: "FFF",
              color: new Color([255, 0, 0])
            }],
            dotValue: dotValue,
            dotSize: 2,
            outline: new SimpleLineSymbol("solid", new Color([50, 50, 50, 1]), 0.5),
            legendOptions: {
              valueUnit: "people",
              backgroundColor: new Color([32, 32, 32])
            }
          });
        };
        
        var rendererInfos = [
          {
            renderer: createRenderer(400),
            maxZoom: 9,
            minZoom: 9
          }, {
            renderer: createRenderer(100),
            maxZoom: 10,
            minZoom: 10
          }, {
            renderer: createRenderer(25),
            maxZoom: 11,
            minZoom: 11
          }, {
            renderer: createRenderer(6),
            maxZoom: 12,
            minZoom: 12
          }
        ];
        
        var scaleDependentRenderer = new ScaleDependentRenderer({
          rendererInfos: rendererInfos
        });
        layer.setRenderer(scaleDependentRenderer);
        map.addLayer(layer);
        
        var legend = new Legend({
          map: map,
          layerInfos: [{ layer: layer }]
        }, "legend");
        legend.startup();
        
        dom.byId("toggle-button").onclick = function(){
          query(".toggle-pane").toggleClass("hidden");
        };
      });
    </script>
  </head>
  <body>
    <div id="map"></div>
    <div id="infopane">
      <div id="toggle-button">[Toggle/expand information pane]</div>
      <div class="toggle-pane">
        <h1 id="info-title">Working Classes in Bay Area</h1>
        <p>DotDensityRenderer provides a way to display multiple attributes for polygon features. A quantitative attribute is represented by dots randomly placed within a polygon.</p>
        <p>The symbols on this map are scale-dependent. As you zoom in, the sizes of symbols are enlarged accordingly.</p>
        <p>Four major working classes are rendered with four distinct colors. One can easily identity clusters by the relative richness of specific a color on the map.</p>
        <div id="legend"></div>
      </div>
    </div>
  </body>
</html> 
 
          
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