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SVG and CSS Transitions

Description

Starting with version 3.7 of the API, features in a GraphicsLayer or FeatureLayer can easily be styled using CSS. This sample shows how to that as well as animating features through time.

Features are animated by through time by repeatedly calling FeatureLayer.redraw(), which, as mentioned previously, causes features to be re-drawn without going back to the server. To re-fetch features from their service, use featureLayer.refresh.

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>USA County Population Change over 25 Years</title>
<link rel="stylesheet" href="https://js.arcgis.com/3.40/esri/css/esri.css">
<style>
  html, body, #mainWindow {
    height: 100%;
    width: 100%;
    margin: 0;
    padding: 0;
  }

  body {
    background-color: white;
    overflow: hidden;
    font-family: "Trebuchet MS";
  }

  #loading {
    background: #fff;
    height: 100%;
    overflow: hidden;
    position: absolute;
    width: 100%;
    z-index: 100;
  }

  #loadingMessage {
    color: #000;
    margin: 0 auto;
    padding: 150px 0 0 0;
    text-align: center;
    width: 200px;
  }

  .shadow {
    -moz-box-shadow: 0 0 5px #888;
    -webkit-box-shadow: 0 0 5px #888;
    box-shadow: 0 0 5px #888;
  }

  #map {
    background-color: white;
  }

  #feedback {
    background: #fff;
    color: #000;
    font-family: arial;
    height: auto;
    left: 30px;
    margin: 5px;
    padding: 10px;
    position: absolute;
    text-align: center;
    top: 30px;
    visibility: hidden;
    width: 200px;
    z-index: 10;
  }

  #currentYear {
    display: inline-block;
    height: 25px;
    text-align: center;
    width: 50px;
  }

  #play, #pause {
    cursor: pointer;
    display: none;
    width: 50px;
  }

  #legend {
    padding: 10px 0 0 0;
  }

  #legend table table td {
    text-align: left;
  }

  /* animate color transition when years change */
  #counties_layer path {
    transition: fill 1.15s, fill-opacity 1.15s, stroke 1.15s, stroke-opacity 1.15s;
    -webkit-transition: fill 1.15s, fill-opacity 1.15s, stroke 1.15s, stroke-opacity 1.15s;
  }

  #counties_layer path[data-relgrowth="no-data"] {
    stroke: rgb(255, 255, 255);
    stroke-width: 1pt;
    stroke-opacity: 1;
  }

  #counties_layer path[data-relgrowth="zero-or-less"] {
    fill: rgb(175, 141, 195); /* purple */
    fill-opacity: 1;
    stroke: rgb(175, 141, 195);
    stroke-width: 1pt;
    stroke-opacity: 1;
  }

  #counties_layer path[data-relgrowth="lt-US"] {
    fill: rgb(225, 236, 231); /* light */
    fill-opacity: 1;
    stroke: rgb(225, 236, 231);
    stroke-width: 1pt;
    stroke-opacity: 1;
  }

  #counties_layer path[data-relgrowth="gt-US"] {
    fill: rgb(127, 191, 123); /* green */
    fill-opacity: 1;
    stroke: rgb(127, 191, 123);
    stroke-width: 1pt;
    stroke-opacity: 1;
  }

</style>

<script src="https://js.arcgis.com/3.40/"></script>
<script>
  require([
    "esri/map",
    "esri/layers/FeatureLayer",
    "esri/dijit/Legend",
    "esri/InfoTemplate",

    "esri/renderers/ClassBreaksRenderer",
    "esri/symbols/SimpleFillSymbol",
    "esri/symbols/SimpleLineSymbol",

    "dojo/_base/array",
    "esri/Color",
    "dojo/_base/fx",
    "dojo/_base/lang",
    "dojo/Deferred",

    "dojo/dom",
    "dojo/dom-construct",
    "dojo/dom-style",
    "dojo/number",
    "dojo/on",
    "dojo/parser",
    "dojo/string",

    "dojox/data/CsvStore",
    "dijit/layout/BorderContainer",
    "dijit/layout/ContentPane",
    "dojo/domReady!"
  ], function (Map, FeatureLayer, Legend, InfoTemplate,
    ClassBreaksRenderer, SimpleFillSymbol, SimpleLineSymbol,
    arrayUtils, Color, fx, lang, Deferred,
    dom, domConstruct, domStyle, number, on, parser, string,
    CsvStore){
    parser.parse();
    var map, layer, currentYear = 1971, currentUSPgr, timer;

    map = new Map("map", {
      basemap: "gray-vector",
      center: [-104.16, 39.342],
      zoom: 3,
      slider: false
    });
    map.on("load", function (){
      loadCSV().then(function (csvData){
        setYear = lang.hitch(csvData, setYear);
        setYear(1971);
        layer = addCounties(csvData);
      });
    });

    // set up play/pause buttons
    on(dom.byId("pause"), "click", function (){
      domStyle.set(this, "display", "none");
      domStyle.set("play", "display", "inline-block");
      pause();
    });
    on(dom.byId("play"), "click", function (){
      domStyle.set(this, "display", "none");
      domStyle.set("pause", "display", "inline-block");
      play();
    });

    function addCounties(csvData){
      var content = "<b>FIPS</b>: ${FIPS} \
                      <br><b>Percent Change</b>: ${RATE}"; // \
      // <br><National Average: ${NATLAVG}";
      var infoTemplate = new InfoTemplate("${NAME} County", content);

      var counties = new FeatureLayer("https://services.arcgis.com/V6ZHFr6zdgNZuVG0/arcgis/rest/services/Census_Counties_20m/FeatureServer/0",
        {
          id: "counties",
          infoTemplate: infoTemplate,
          outFields: ["NAME", "FIPS"],
          styling: false
        });

      counties.on("load", function (){
        on.once(counties, "update-end", function (){
          var renderer = createRenderer(currentYear, "FIPS", csvData);
          counties.setRenderer(renderer);
          createLegend(counties);
          domStyle.set("pause", "display", "inline-block");
          play();
        });
        fadeOutLoading();
      });

      if (counties.surfaceType === "svg") {
        counties.on("graphic-draw", function (evt){
          var attrs = evt.graphic.attributes;
          var joinKey = attrs && attrs.FIPS;
          var relgrowth = "no-data";

          if (joinKey && csvData[joinKey] && csvData[joinKey][currentYear]) {
            var countyPgr = getGrowthRate(csvData[joinKey][currentYear - 1], csvData[joinKey][currentYear], 1);

            relgrowth = (countyPgr <= 0) ? "zero-or-less" :
              (countyPgr <= currentUSPgr) ? "lt-US" : "gt-US";
          }
          attrs.RATE = number.round(countyPgr, 2) + "%";
          evt.graphic.getNode().setAttribute("data-relgrowth", relgrowth);
        });
      }

      map.addLayer(counties);
      return counties;
    }

    function loadCSV(){
      var dfd = new Deferred();

      var csvStore = new CsvStore({
        url: "county_population.csv"
      });

      csvStore.fetch({
        onComplete: function (items, request){  //process csv data and create in memory object store.
          var store = request.store;
          var minYearPopulation = 1970;
          var maxYearPopulation = 2006;
          var counties = {};

          counties.minVal = Infinity;
          counties.maxVal = -Infinity;

          arrayUtils.forEach(items, function (item){
            var countyFips = store.getValue(item, "county_fips");
            var stateFips = store.getValue(item, "state_fips");
            var fips = string.pad(stateFips, 2, "0") + string.pad(countyFips, 3, "0");
            var population = {};

            population.maxVal = -Infinity;

            for (var year = minYearPopulation; year <= maxYearPopulation; year++) {
              var fieldName = "pop" + year;
              var popValue = parseInt(store.getValue(item, fieldName), 10);
              population[year] = popValue;
              population.maxVal = (popValue > population.maxVal) ? popValue : population.maxVal;
              counties.minVal = (popValue < counties.minVal) ? popValue : counties.minVal;
              counties.maxVal = (popValue > counties.maxVal) ? popValue : counties.maxVal;
            }

            counties[fips] = population;
          });
          dfd.resolve(counties);
        },
        onError: function (err){
          console.log("Error loading CSV: ", err.message, err);
        }
      });
      return dfd;
    }

    function getGrowthRate(pt1, pt2, t2_t1){
      return ((Math.log(pt2) - Math.log(pt1)) / (t2_t1)) * 100;
    }

    function setYear(year){
      var csvData = this;
      currentYear = year;
      currentUSPgr = getGrowthRate(csvData["00000"][currentYear - 1], csvData["00000"][currentYear], 1);
      dom.byId("currentYear").innerHTML = currentYear;

      if (layer) {
        layer.renderer._currentYear = year;
        addBreaks(layer.renderer);
        layer.redraw();
        var sel = map.infoWindow.getSelectedFeature();
        if (sel && map.infoWindow.isShowing) {
          map.infoWindow.setFeatures([sel]);
        }
      }
    }

    function changeYear(incr){
      var year;
      if (incr < 1) {
        year = (currentYear === 1971) ? 2006 : currentYear + incr;
        setYear(year);
      }
      else if (incr > 0) {
        year = (currentYear === 2006) ? 1971 : currentYear + incr;
        setYear(year);
      }
    }

    function play(){
      if (!timer) {
        timer = setInterval(function (){
          changeYear(1);
        }, 1250);
      }
    }

    function pause(){
      clearInterval(timer);
      timer = null;
    }

    function createRenderer(startYear, joinField, data){
      // renderer is used for the legend
      var renderer = new ClassBreaksRenderer(null, "FIPS");
      renderer._currentYear = startYear;
      renderer._data = data;
      addBreaks(renderer);
      // console.log("renderer with breaks", renderer);
      return renderer;
    }

    function createLegend(layer){
      var legendDijit = new Legend({
        map: map,
        layerInfos: [
          {
            "layer": layer,
            "title": "Population Change"
          }
        ]
      }, "legend");
      legendDijit.startup();
      domStyle.set("feedback", "visibility", "visible");
    }

    function addBreaks(renderer){
      // console.log("addBreaks", renderer);
      var currentYear = renderer._currentYear,
          data = renderer._data,
          totalGrowth = getGrowthRate(data['00000'][currentYear], data['00000'][currentYear - 1], 1),
          roundedTotalGrowth = number.round(totalGrowth, 2);

      renderer.clearBreaks();

      var negative = [175, 141, 195];
      var flat = [225, 236, 231];
      var positive = [127, 191, 123];

      renderer.addBreak({
        minValue: -Infinity,
        maxValue: 0,
        symbol: new SimpleFillSymbol().setColor(new Color(negative))
          .setOutline(new SimpleLineSymbol().setColor(new Color(negative))),
        label: "Decrease"
      });

      renderer.addBreak({
        minValue: 0,
        maxValue: roundedTotalGrowth,
        symbol: new SimpleFillSymbol().setColor(new Color(flat))
          .setOutline(new SimpleLineSymbol().setColor(new Color(flat))),
        label: "Flat"
      });

      renderer.addBreak({
        minValue: roundedTotalGrowth,
        maxValue: Infinity,
        symbol: new SimpleFillSymbol().setColor(new Color(positive))
          .setOutline(new SimpleLineSymbol().setColor(new Color(positive))),
        label: "Increase"
      });
    }

    function fadeOutLoading(){
      var fade = fx.fadeOut({
        node: "loading",
        onEnd: function (){
          domConstruct.destroy(dom.byId("loading"));
        }
      });
      fade.play();
    }
  });
  </script>
</head>

<body>
  <div id="loading">
    <div id="loadingMessage">
      Loading County and Population Data
      <br>
      <img src="assets/loading_gray_circle.gif">
    </div>
  </div>
  <div id="mainWindow" data-dojo-type="dijit/layout/BorderContainer" data-dojo-props="'design': 'headline', 'gutters': false">
    <div id="map" data-dojo-type="dijit/layout/ContentPane" data-dojo-props="'region': 'center'">
      <div id="feedback" class="shadow">
        Year:
        <span id="currentYear">...</span>
        |
        <span id="play">Play</span>
        <span id="pause">Pause</span>
        <div id="legend"></div>
      </div>

    </div> 
  </div> 
</body>
</html>
 
          
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