curran/README.md

## README.md

      
    Raw
  

              README.md
            
          
    This program makes a scatter plot from Iris data set. Brushing in one plot zooms in the other.

  
## index.html
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">

    <!-- Use RequireJS for module loading. -->
    <script src="//cdnjs.cloudflare.com/ajax/libs/require.js/2.1.14/require.js"></script>

    <!-- Configure AMD modules. -->
    <script>
      requirejs.config({
        paths: {
          d3: "//d3js.org/d3.v3.min",
          jquery: "//code.jquery.com/jquery-2.1.1.min"
        }
      });
    </script>

    <!-- Include CSS that styles the visualization. -->
    <link rel="stylesheet" href="styles.css">

    <title>Scatter Plot</title>
  </head>
  <body>

    <!-- The visualization will be injected into this div. -->
    <div id="container"></div>

    <!-- Run the main program. -->
    <script src="main.js"></script>

  </body>
</html>

## iris-metadata.json
{
  "sepal_length":{
    "type": "Q",
    "label": "sepal length (cm)"
  },
  "sepal_width": {
    "type": "Q",
    "label": "sepal width (cm)"
  },
  "petal_length": {
    "type": "Q",
    "label": "petal length (cm)"
  },
  "petal_width": {
    "type": "Q",
    "label": "petal width (cm)"
  },
  "class": {
    "type": "N",
    "label": "species"
  }
}

## iris.csv

          
            sepal_length
            sepal_width
            petal_length
            petal_width
            class

            
              5.1
              3.5
              1.4
              0.2
              Iris-setosa

            
              4.9
              3.0
              1.4
              0.2
              Iris-setosa

            
              4.7
              3.2
              1.3
              0.2
              Iris-setosa

            
              4.6
              3.1
              1.5
              0.2
              Iris-setosa

            
              5.0
              3.6
              1.4
              0.2
              Iris-setosa

            
              5.4
              3.9
              1.7
              0.4
              Iris-setosa

            
              4.6
              3.4
              1.4
              0.3
              Iris-setosa

            
              5.0
              3.4
              1.5
              0.2
              Iris-setosa

            
              4.4
              2.9
              1.4
              0.2
              Iris-setosa

            
              4.9
              3.1
              1.5
              0.1
              Iris-setosa

            
              5.4
              3.7
              1.5
              0.2
              Iris-setosa

            
              4.8
              3.4
              1.6
              0.2
              Iris-setosa

            
              4.8
              3.0
              1.4
              0.1
              Iris-setosa

            
              4.3
              3.0
              1.1
              0.1
              Iris-setosa

            
              5.8
              4.0
              1.2
              0.2
              Iris-setosa

            
              5.7
              4.4
              1.5
              0.4
              Iris-setosa

            
              5.4
              3.9
              1.3
              0.4
              Iris-setosa

            
              5.1
              3.5
              1.4
              0.3
              Iris-setosa

            
              5.7
              3.8
              1.7
              0.3
              Iris-setosa

            
              5.1
              3.8
              1.5
              0.3
              Iris-setosa

            
              5.4
              3.4
              1.7
              0.2
              Iris-setosa

            
              5.1
              3.7
              1.5
              0.4
              Iris-setosa

            
              4.6
              3.6
              1.0
              0.2
              Iris-setosa

            
              5.1
              3.3
              1.7
              0.5
              Iris-setosa

            
              4.8
              3.4
              1.9
              0.2
              Iris-setosa

            
              5.0
              3.0
              1.6
              0.2
              Iris-setosa

            
              5.0
              3.4
              1.6
              0.4
              Iris-setosa

            
              5.2
              3.5
              1.5
              0.2
              Iris-setosa

            
              5.2
              3.4
              1.4
              0.2
              Iris-setosa

            
              4.7
              3.2
              1.6
              0.2
              Iris-setosa

            
              4.8
              3.1
              1.6
              0.2
              Iris-setosa

            
              5.4
              3.4
              1.5
              0.4
              Iris-setosa

            
              5.2
              4.1
              1.5
              0.1
              Iris-setosa

            
              5.5
              4.2
              1.4
              0.2
              Iris-setosa

            
              4.9
              3.1
              1.5
              0.1
              Iris-setosa

            
              5.0
              3.2
              1.2
              0.2
              Iris-setosa

            
              5.5
              3.5
              1.3
              0.2
              Iris-setosa

            
              4.9
              3.1
              1.5
              0.1
              Iris-setosa

            
              4.4
              3.0
              1.3
              0.2
              Iris-setosa

            
              5.1
              3.4
              1.5
              0.2
              Iris-setosa

            
              5.0
              3.5
              1.3
              0.3
              Iris-setosa

            
              4.5
              2.3
              1.3
              0.3
              Iris-setosa

            
              4.4
              3.2
              1.3
              0.2
              Iris-setosa

            
              5.0
              3.5
              1.6
              0.6
              Iris-setosa

            
              5.1
              3.8
              1.9
              0.4
              Iris-setosa

            
              4.8
              3.0
              1.4
              0.3
              Iris-setosa

            
              5.1
              3.8
              1.6
              0.2
              Iris-setosa

            
              4.6
              3.2
              1.4
              0.2
              Iris-setosa

            
              5.3
              3.7
              1.5
              0.2
              Iris-setosa

            
              5.0
              3.3
              1.4
              0.2
              Iris-setosa

            
              7.0
              3.2
              4.7
              1.4
              Iris-versicolor

            
              6.4
              3.2
              4.5
              1.5
              Iris-versicolor

            
              6.9
              3.1
              4.9
              1.5
              Iris-versicolor

            
              5.5
              2.3
              4.0
              1.3
              Iris-versicolor

            
              6.5
              2.8
              4.6
              1.5
              Iris-versicolor

            
              5.7
              2.8
              4.5
              1.3
              Iris-versicolor

            
              6.3
              3.3
              4.7
              1.6
              Iris-versicolor

            
              4.9
              2.4
              3.3
              1.0
              Iris-versicolor

            
              6.6
              2.9
              4.6
              1.3
              Iris-versicolor

            
              5.2
              2.7
              3.9
              1.4
              Iris-versicolor

            
              5.0
              2.0
              3.5
              1.0
              Iris-versicolor

            
              5.9
              3.0
              4.2
              1.5
              Iris-versicolor

            
              6.0
              2.2
              4.0
              1.0
              Iris-versicolor

            
              6.1
              2.9
              4.7
              1.4
              Iris-versicolor

            
              5.6
              2.9
              3.6
              1.3
              Iris-versicolor

            
              6.7
              3.1
              4.4
              1.4
              Iris-versicolor

            
              5.6
              3.0
              4.5
              1.5
              Iris-versicolor

            
              5.8
              2.7
              4.1
              1.0
              Iris-versicolor

            
              6.2
              2.2
              4.5
              1.5
              Iris-versicolor

            
              5.6
              2.5
              3.9
              1.1
              Iris-versicolor

            
              5.9
              3.2
              4.8
              1.8
              Iris-versicolor

            
              6.1
              2.8
              4.0
              1.3
              Iris-versicolor

            
              6.3
              2.5
              4.9
              1.5
              Iris-versicolor

            
              6.1
              2.8
              4.7
              1.2
              Iris-versicolor

            
              6.4
              2.9
              4.3
              1.3
              Iris-versicolor

            
              6.6
              3.0
              4.4
              1.4
              Iris-versicolor

            
              6.8
              2.8
              4.8
              1.4
              Iris-versicolor

            
              6.7
              3.0
              5.0
              1.7
              Iris-versicolor

            
              6.0
              2.9
              4.5
              1.5
              Iris-versicolor

            
              5.7
              2.6
              3.5
              1.0
              Iris-versicolor

            
              5.5
              2.4
              3.8
              1.1
              Iris-versicolor

            
              5.5
              2.4
              3.7
              1.0
              Iris-versicolor

            
              5.8
              2.7
              3.9
              1.2
              Iris-versicolor

            
              6.0
              2.7
              5.1
              1.6
              Iris-versicolor

            
              5.4
              3.0
              4.5
              1.5
              Iris-versicolor

            
              6.0
              3.4
              4.5
              1.6
              Iris-versicolor

            
              6.7
              3.1
              4.7
              1.5
              Iris-versicolor

            
              6.3
              2.3
              4.4
              1.3
              Iris-versicolor

            
              5.6
              3.0
              4.1
              1.3
              Iris-versicolor

            
              5.5
              2.5
              4.0
              1.3
              Iris-versicolor

            
              5.5
              2.6
              4.4
              1.2
              Iris-versicolor

            
              6.1
              3.0
              4.6
              1.4
              Iris-versicolor

            
              5.8
              2.6
              4.0
              1.2
              Iris-versicolor

            
              5.0
              2.3
              3.3
              1.0
              Iris-versicolor

            
              5.6
              2.7
              4.2
              1.3
              Iris-versicolor

            
              5.7
              3.0
              4.2
              1.2
              Iris-versicolor

            
              5.7
              2.9
              4.2
              1.3
              Iris-versicolor

            
              6.2
              2.9
              4.3
              1.3
              Iris-versicolor

            
              5.1
              2.5
              3.0
              1.1
              Iris-versicolor

            
              5.7
              2.8
              4.1
              1.3
              Iris-versicolor

            
              6.3
              3.3
              6.0
              2.5
              Iris-virginica

            
              5.8
              2.7
              5.1
              1.9
              Iris-virginica

            
              7.1
              3.0
              5.9
              2.1
              Iris-virginica

            
              6.3
              2.9
              5.6
              1.8
              Iris-virginica

            
              6.5
              3.0
              5.8
              2.2
              Iris-virginica

            
              7.6
              3.0
              6.6
              2.1
              Iris-virginica

            
              4.9
              2.5
              4.5
              1.7
              Iris-virginica

            
              7.3
              2.9
              6.3
              1.8
              Iris-virginica

            
              6.7
              2.5
              5.8
              1.8
              Iris-virginica

            
              7.2
              3.6
              6.1
              2.5
              Iris-virginica

            
              6.5
              3.2
              5.1
              2.0
              Iris-virginica

            
              6.4
              2.7
              5.3
              1.9
              Iris-virginica

            
              6.8
              3.0
              5.5
              2.1
              Iris-virginica

            
              5.7
              2.5
              5.0
              2.0
              Iris-virginica

            
              5.8
              2.8
              5.1
              2.4
              Iris-virginica

            
              6.4
              3.2
              5.3
              2.3
              Iris-virginica

            
              6.5
              3.0
              5.5
              1.8
              Iris-virginica

            
              7.7
              3.8
              6.7
              2.2
              Iris-virginica

            
              7.7
              2.6
              6.9
              2.3
              Iris-virginica

            
              6.0
              2.2
              5.0
              1.5
              Iris-virginica

            
              6.9
              3.2
              5.7
              2.3
              Iris-virginica

            
              5.6
              2.8
              4.9
              2.0
              Iris-virginica

            
              7.7
              2.8
              6.7
              2.0
              Iris-virginica

            
              6.3
              2.7
              4.9
              1.8
              Iris-virginica

            
              6.7
              3.3
              5.7
              2.1
              Iris-virginica

            
              7.2
              3.2
              6.0
              1.8
              Iris-virginica

            
              6.2
              2.8
              4.8
              1.8
              Iris-virginica

            
              6.1
              3.0
              4.9
              1.8
              Iris-virginica

            
              6.4
              2.8
              5.6
              2.1
              Iris-virginica

            
              7.2
              3.0
              5.8
              1.6
              Iris-virginica

            
              7.4
              2.8
              6.1
              1.9
              Iris-virginica

            
              7.9
              3.8
              6.4
              2.0
              Iris-virginica

            
              6.4
              2.8
              5.6
              2.2
              Iris-virginica

            
              6.3
              2.8
              5.1
              1.5
              Iris-virginica

            
              6.1
              2.6
              5.6
              1.4
              Iris-virginica

            
              7.7
              3.0
              6.1
              2.3
              Iris-virginica

            
              6.3
              3.4
              5.6
              2.4
              Iris-virginica

            
              6.4
              3.1
              5.5
              1.8
              Iris-virginica

            
              6.0
              3.0
              4.8
              1.8
              Iris-virginica

            
              6.9
              3.1
              5.4
              2.1
              Iris-virginica

            
              6.7
              3.1
              5.6
              2.4
              Iris-virginica

            
              6.9
              3.1
              5.1
              2.3
              Iris-virginica

            
              5.8
              2.7
              5.1
              1.9
              Iris-virginica

            
              6.8
              3.2
              5.9
              2.3
              Iris-virginica

            
              6.7
              3.3
              5.7
              2.5
              Iris-virginica

            
              6.7
              3.0
              5.2
              2.3
              Iris-virginica

            
              6.3
              2.5
              5.0
              1.9
              Iris-virginica

            
              6.5
              3.0
              5.2
              2.0
              Iris-virginica

            
              6.2
              3.4
              5.4
              2.3
              Iris-virginica

            
              5.9
              3.0
              5.1
              1.8
              Iris-virginica

## main.js
// This is the main program that sets up a scatter plot to visualize the Iris data set.
// Curran Kelleher March 2015
require(["scatterPlot"], function (ScatterPlot) {

  // Initialize the scatter plot.
  var options = {

        // Tell the visualization which DOM element to insert itself into.
        container: d3.select("#container").node(),

        // Specify the margin and text label offsets.
        margin: {
          top: 10,
          right: 10,
          bottom: 45,
          left: 55
        },
        yAxisLabelOffset: 1.8, // Unit is CSS "em"s
        xAxisLabelOffset: 1.9,
        titleOffset: 0.3
      },
      scatterPlot1 = ScatterPlot(options),
      scatterPlot2 = ScatterPlot(options);

  // Fetch the column metadata.
  d3.json("iris-metadata.json", function (metadata) {

    var xColumn = "sepal_length",
        yColumn = "petal_length",
        sizeColumn = "petal_width",
        colorColumn = "class",
        xyOptions = {
          xColumn: xColumn,
          xAxisLabel: metadata[xColumn].label,
          yColumn: yColumn,
          yAxisLabel: metadata[yColumn].label
        };

    // Use the same X and Y for all plots.
    scatterPlot1.set(xyOptions);
    scatterPlot2.set(xyOptions);

    // Load the data from a CSV file.
    d3.csv("iris.csv", function (data){

      // Parse quantitative values from strings to numbers.
      var quantitativeColumns = Object.keys(metadata).filter(function (column){
        return metadata[column].type === "Q";
      });
      data.forEach(function (d){
        quantitativeColumns.forEach(function (column){
          d[column] = parseFloat(d[column]);
        });
      });

      // Pass the data into the plots.
      scatterPlot1.data = data;
      scatterPlot2.data = data;
    });

    // Use the first plot to zoom in the second plot.
    scatterPlot1.brushEnabled = true;
    scatterPlot1.when("brushedIntervals", function (brushedIntervals){
      scatterPlot2.xDomainMin = brushedIntervals[xColumn][0];
      scatterPlot2.xDomainMax = brushedIntervals[xColumn][1];
      scatterPlot2.yDomainMin = brushedIntervals[yColumn][0];
      scatterPlot2.yDomainMax = brushedIntervals[yColumn][1];
    });

    // Initialize the default brush.
    scatterPlot1.brushedIntervals = {
      "sepal_length": [ 4.82, 7.77 ],
      "petal_length": [ 2.84, 6.80 ]
    };
  });

  // Sets the `box` model property
  // based on the size of the container,
  function computeBoxes(){
    var width = container.clientWidth,
        height = container.clientHeight,
        padding = 10,
        plotWidth = (width - padding * 2) / 2,
        plotHeight = height - padding * 2;
    scatterPlot1.box = {
      x: padding,
      y: padding,
      width: plotWidth,
      height: plotHeight
    };
    scatterPlot2.box = {
      x: plotWidth + padding * 2,
      y: padding,
      width: plotWidth,
      height: plotHeight
    };
  }

  // once to initialize `model.box`, and
  computeBoxes();

  // whenever the browser window resizes in the future.
  window.addEventListener("resize", computeBoxes);
});

## model.js
// A functional reactive model library.
//
(function(){

  // The D3 conventional graph representation.
  // See https://github.com/mbostock/d3/wiki/Force-Layout#nodes
  var nodes, links, idCounter, map;

  function resetFlowGraph(){
    nodes = [];
    links = [];
    idCounter = 0;
    map = {};
  }

  function getFlowGraph(){
    return {
      nodes: nodes,
      links: links
    };
  }

  resetFlowGraph();

  // Adds the nodes and links to the data flow graph for one
  // particular reactive function.
  function updateLambda(modelId, lambdaId, inProperties, outProperties){
    var lambda = lambdaNode(lambdaId);
    inProperties.forEach(function(property){
      link(propertyNode(modelId, property), lambda);
    });
    outProperties.forEach(function(property){
      link(lambda, propertyNode(modelId, property));
    });
  }

  function lambdaNode(id){
    return getOrCreate(id, nodes, createLambda);
  }

  function createLambda(index){
    return {
      type: "lambda",
      index: index
    };
  }

  function propertyNode(modelId, property){
    var id = modelId + "." + property;
    return getOrCreate(id, nodes, createPropertyNode(property));
  }

  function createPropertyNode(property){
    return function(index){
      return {
        type: "property",
        index: index,
        property: property
      };
    };
  }

  function link(sourceNode, targetNode){
    var source = sourceNode.index,
        target = targetNode.index,
        id = source + "-" + target;
    getOrCreate(id, links, createLink(source, target));
  }

  function createLink(source, target){
    return function(index){
      return {
        source: source,
        target: target
      };
    };
  }

  function getOrCreate(id, things, createThing){
    var thing = map[id];
    if(!thing){
      thing = map[id] = createThing(things.length);
      things.push(thing);
    }
    return thing;
  }

  // The constructor function, accepting default values.
  function Model(defaults){

    // The returned public API object.
    var model = {},

        // The internal stored values for tracked properties. { property -> value }
        values = {},

        // The callback functions for each tracked property. { property -> [callback] }
        listeners = {},

        // The set of tracked properties. { property -> true }
        trackedProperties = {},

        modelId = idCounter++,
        changedProperties = {};

    // The functional reactive "when" operator.
    //
    //  * `properties` An array of property names (can also be a single property string).
    //  * `callback` A callback function that is called:
    //    * with property values as arguments, ordered corresponding to the properties array,
    //    * only if all specified properties have values,
    //    * once for initialization,
    //    * whenever one or more specified properties change,
    //    * on the next tick of the JavaScript event loop after properties change,
    //    * only once as a result of one or more synchronous changes to dependency properties.
    function when(properties, callback, thisArg){

      var lambdaId = idCounter++;

      // Make sure the default `this` becomes
      // the object you called `.on` on.
      thisArg = thisArg || this;

      // Handle either an array or a single string.
      properties = (properties instanceof Array) ? properties : [properties];

      // This function will trigger the callback to be invoked.
      var triggerCallback = debounce(function (){
        var args = properties.map(function(property){
          return values[property];
        });
        if(allAreDefined(args)){
          changedProperties = {};

          callback.apply(thisArg, args);

          updateLambda(modelId, lambdaId, properties, Object.keys(changedProperties));
        }
      });

      // Trigger the callback once for initialization.
      triggerCallback();

      // Trigger the callback whenever specified properties change.
      properties.forEach(function(property){
        on(property, triggerCallback);
      });

      // Return this function so it can be removed later.
      return triggerCallback;
    }

    // Returns a debounced version of the given function.
    // See http://underscorejs.org/#debounce
    function debounce(callback){
      var queued = false;
      return function () {
        if(!queued){
          queued = true;
          setTimeout(function () {
            queued = false;
            callback();
          }, 0);
        }
      };
    }

    // Returns true if all elements of the given array are defined, false otherwise.
    function allAreDefined(arr){
      return !arr.some(function (d) {
        return typeof d === 'undefined' || d === null;
      });
    }

    // Adds a change listener for a given property with Backbone-like behavior.
    // Similar to http://backbonejs.org/#Events-on
    function on(property, callback, thisArg){

      // Make sure the default `this` becomes
      // the object you called `.on` on.
      thisArg = thisArg || this;
      getListeners(property).push(callback);
      track(property, thisArg);
    }

    // Gets or creates the array of listener functions for a given property.
    function getListeners(property){
      return listeners[property] || (listeners[property] = []);
    }

    // Tracks a property if it is not already tracked.
    function track(property, thisArg){
      if(!(property in trackedProperties)){
        trackedProperties[property] = true;
        values[property] = model[property];
        Object.defineProperty(model, property, {
          get: function () { return values[property]; },
          set: function(newValue) {
            var oldValue = values[property];
            values[property] = newValue;
            getListeners(property).forEach(function(callback){
              callback.call(thisArg, newValue, oldValue);
            });

            changedProperties[property] = true;
          }
        });
      }
    }

    // Removes a listener added using `when()`.
    function cancel(listener){
      for(var property in listeners){
        off(property, listener);
      }
    }

    // Removes a change listener added using `on`.
    function off(property, callback){
      listeners[property] = listeners[property].filter(function (listener) {
        return listener !== callback;
      });
    }

    // Sets all of the given values on the model.
    // `newValues` is an object { property -> value }.
    function set(newValues){
      for(var property in newValues){
        model[property] = newValues[property];
      }
    }

    // Transfer defaults passed into the constructor to the model.
    set(defaults);

    // Expose the public API.
    model.when = when;
    model.cancel = cancel;
    model.on = on;
    model.off = off;
    model.set = set;
    return model;
  }

  Model.getFlowGraph = getFlowGraph;
  Model.resetFlowGraph = resetFlowGraph;

  // Support AMD (RequireJS), CommonJS (Node), and browser globals.
  // Inspired by https://github.com/umdjs/umd
  if (typeof define === "function" && define.amd) {
    define([], function () { return Model; });
  } else if (typeof exports === "object") {
    module.exports = Model;
  } else {
    this.Model = Model;
  }
})();

## scatterPlot.js
// A reusable scatter plot module.
// Curran Kelleher March 2015
define(["d3", "model"], function (d3, Model) {

  // A representation for an optional Model property that is not specified.
  // This allows the "when" approach to support optional properties.
  // Inspired by Scala's Option type.
  // See http://alvinalexander.com/scala/using-scala-option-some-none-idiom-function-java-null
  var None = "__none__";

  // The constructor function, accepting default values.
  return function ScatterPlot(defaults) {

    // Create a Model instance for the visualization.
    // This will serve as its public API.
    var model = Model();

    // Create an SVG element from the container DOM element.
    model.when("container", function (container) {
      model.svg = d3.select(container).append("svg")

        // Use CSS `position: absolute;`
        // so setting `left` and `top` later will
        // position the SVG relative to the container div.
        .style("position", "absolute");
    });

    // Adjust the size of the SVG based on the `box` property.
    model.when(["svg", "box"], function (svg, box) {

      // Set the CSS `left` and `top` properties
      // to move the SVG to `(box.x, box.y)`
      // relative to the container div.
      svg
        .style("left", box.x + "px")
        .style("top", box.y + "px")
        .attr("width", box.width)
        .attr("height", box.height);
    });

    // Create an SVG group that will contain the visualization.
    model.when("svg", function (svg) {
      model.g = svg.append("g");
    });

    model.when("g", function (g) {

      // Add an SVG group to contain the marks.
      model.circlesG = g.append("g");

      // Create a group for the brush.
      model.brushG = g.append("g").attr("class", "brush");

      // The circles group is added first, before the brush group,
      // so that mouse events go to the brush rather than to the
      // circles, even when the mouse is on top of a circle.
    });

    // Disable brushing by default.
    model.brushEnabled = false;

    // Set up brushing interactions to define `brushedIntervals` on the model.
    model.when(["brushEnabled", "xColumn", "yColumn", "xScale", "yScale"],
        function (brushEnabled, xColumn, yColumn, xScale, yScale) {
      if(brushEnabled){
        var brush = d3.svg.brush();
        brush.on("brush", function () {
          model.brushedIntervals = brushToIntervals(brush, xColumn, yColumn, xScale, yScale);
        });
        model.brush = brush;
      }
    });


    function brushToIntervals(brush, xColumn, yColumn, xScale, yScale){
      var brushedIntervals = {};
      if(!brush.empty()
      && brush.extent() !== null){
        var e = brush.extent(),
            xMin = e[0][0],
            yMin = e[0][1],
            xMax = e[1][0],
            yMax = e[1][1],
            epsilon = 0.01;

        // Account for the edge case where the brush is at the
        // X or Y min or max. Adding a small value ensures that all
        // points are included when crossfilter's filterRange is used,
        // because filterRange provides an exclusive range, not inclusive.
        // See https://github.com/square/crossfilter/wiki/API-Reference#dimension_filterRange
        if(xMax === xScale.domain()[1]){ xMax += epsilon; }
        if(yMax === yScale.domain()[1]){ yMax += epsilon; }
        if(xMin === xScale.domain()[0]){ xMin -= epsilon; }
        if(yMin === yScale.domain()[0]){ yMin -= epsilon; }

        brushedIntervals[xColumn] = [xMin, xMax];
        brushedIntervals[yColumn] = [yMin, yMax];
      } else {
        brushedIntervals[xColumn] = [None, None];
        brushedIntervals[yColumn] = [None, None];
      }
      return brushedIntervals;
    }

    function intervalsToBrush(brushedIntervals, xColumn, yColumn){
      return [
        [brushedIntervals[xColumn][0], brushedIntervals[yColumn][0]],
        [brushedIntervals[xColumn][1], brushedIntervals[yColumn][1]]
      ];
    }

    // Update the rendered brush.
    model.when(["brushedIntervals", "brush", "brushG", "xColumn", "yColumn", "xScale", "yScale"],
        function (brushedIntervals, brush, brushG, xColumn, yColumn, xScale, yScale) {

      // Update the scales within the brush.
      brush.x(xScale);
      brush.y(yScale);

      // Update the extent of the brush.
      brush.extent(intervalsToBrush(brushedIntervals, xColumn, yColumn));

      // Render the brush onto the brush group.
      brushG.call(brush);
    });

    // Adjust the SVG group translation based on the margin.
    model.when(["g", "margin"], function (g, margin) {
      g.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
    });

    // Create the title text element.
    model.when("g", function (g){
      model.titleText = g.append("text").attr("class", "title-text");
    });

    // Center the title text when width changes.
    model.when(["titleText", "width"], function (titleText, width) {
      titleText.attr("x", width / 2);
    });

    // Update the title text based on the `title` property.
    model.when(["titleText", "title"], function (titleText, title){
      titleText.text(title);
    });

    // Update the title text offset.
    model.when(["titleText", "titleOffset"], function (titleText, titleOffset){
      titleText.attr("dy", titleOffset + "em");
    });

    // Compute the inner box from the outer box and margin.
    // See Margin Convention http://bl.ocks.org/mbostock/3019563
    model.when(["box", "margin"], function (box, margin) {
      model.width = box.width - margin.left - margin.right;
      model.height = box.height - margin.top - margin.bottom;
    });

    // Generate a function for getting the X value.
    model.when(["data", "xColumn"], function (data, xColumn) {
      model.getX = function (d) { return d[xColumn]; };
    });

    // Compute the domain of the X attribute.

    // Allow the API client to optionally specify fixed min and max values.
    model.xDomainMin = None;
    model.xDomainMax = None;
    model.when(["data", "getX", "xDomainMin", "xDomainMax"],
        function (data, getX, xDomainMin, xDomainMax) {

      if(xDomainMin === None && xDomainMax === None){
        model.xDomain = d3.extent(data, getX);
      } else {
        if(xDomainMin === None){
          xDomainMin = d3.min(data, getX);
        }
        if(xDomainMax === None){
          xDomainMax = d3.max(data, getX);
        }
        model.xDomain = [xDomainMin, xDomainMax]
      }
    });

    // Compute the X scale.
    model.when(["xDomain", "width"], function (xDomain, width) {
      model.xScale = d3.scale.linear().domain(xDomain).range([0, width]);
    });

    // Generate a function for getting the scaled X value.
    model.when(["data", "xScale", "getX"], function (data, xScale, getX) {
      model.getXScaled = function (d) { return xScale(getX(d)); };
    });

    // Set up the X axis.
    model.when("g", function (g) {
      model.xAxisG = g.append("g").attr("class", "x axis");
      model.xAxisText = model.xAxisG.append("text").style("text-anchor", "middle");
    });

    // Move the X axis label based on its specified offset.
    model.when(["xAxisText", "xAxisLabelOffset"], function (xAxisText, xAxisLabelOffset){
      xAxisText.attr("dy", xAxisLabelOffset + "em");
    });

    // Update the X axis transform when height changes.
    model.when(["xAxisG", "height"], function (xAxisG, height) {
      xAxisG.attr("transform", "translate(0," + height + ")");
    });

    // Center the X axis label when width changes.
    model.when(["xAxisText", "width"], function (xAxisText, width) {
      xAxisText.attr("x", width / 2);
    });

    // Update the X axis based on the X scale.
    model.when(["xAxisG", "xScale"], function (xAxisG, xScale) {
      xAxisG.call(d3.svg.axis().orient("bottom").scale(xScale));
    });

    // Update X axis label.
    model.when(["xAxisText", "xAxisLabel"], function (xAxisText, xAxisLabel) {
      xAxisText.text(xAxisLabel);
    });

    // Generate a function for getting the Y value.
    model.when(["data", "yColumn"], function (data, yColumn) {
      model.getY = function (d) { return d[yColumn]; };
    });

    // Compute the domain of the Y attribute.

    // Allow the API client to optionally specify fixed min and max values.
    model.yDomainMin = None;
    model.yDomainMax = None;
    model.when(["data", "getY", "yDomainMin", "yDomainMax"],
        function (data, getY, yDomainMin, yDomainMax) {

      if(yDomainMin === None && yDomainMax === None){
        model.yDomain = d3.extent(data, getY);
      } else {
        if(yDomainMin === None){
          yDomainMin = d3.min(data, getY);
        }
        if(yDomainMax === None){
          yDomainMax = d3.max(data, getY);
        }
        model.yDomain = [yDomainMin, yDomainMax]
      }
    });

    // Compute the Y scale.
    model.when(["data", "yDomain", "height"], function (data, yDomain, height) {
      model.yScale = d3.scale.linear().domain(yDomain).range([height, 0]);
    });

    // Generate a function for getting the scaled Y value.
    model.when(["data", "yScale", "getY"], function (data, yScale, getY) {
      model.getYScaled = function (d) { return yScale(getY(d)); };
    });

    // Set up the Y axis.
    model.when("g", function (g) {
      model.yAxisG = g.append("g").attr("class", "y axis");
      model.yAxisText = model.yAxisG.append("text")
        .style("text-anchor", "middle")
        .attr("transform", "rotate(-90)")
        .attr("y", 0);
    });

    // Move the Y axis label based on its specified offset.
    model.when(["yAxisText", "yAxisLabelOffset"], function (yAxisText, yAxisLabelOffset){
      yAxisText.attr("dy", "-" + yAxisLabelOffset + "em")
    });

    // Center the Y axis label when height changes.
    model.when(["yAxisText", "height"], function (yAxisText, height) {
      yAxisText.attr("x", -height / 2);
    });

    // Update Y axis label.
    model.when(["yAxisText", "yAxisLabel"], function (yAxisText, yAxisLabel) {
      yAxisText.text(yAxisLabel);
    });

    // Update the Y axis based on the Y scale.
    model.when(["yAxisG", "yScale"], function (yAxisG, yScale) {
      yAxisG.call(d3.svg.axis().orient("left").scale(yScale));
    });

    // Allow the API client to optionally specify a size column.
    model.sizeColumn = None;

    // The default radius of circles in pixels.
    model.sizeDefault = 2;

    // The min and max circle radius in pixels.
    model.sizeMin = 0.5;
    model.sizeMax = 6;

    // Set up the size scale.
    model.when(["sizeColumn", "data", "sizeDefault", "sizeMin", "sizeMax"],
        function (sizeColumn, data, sizeDefault, sizeMin, sizeMax){
      if(sizeColumn !== None){
        var getSize = function (d){ return d[sizeColumn] },
            sizeScale = d3.scale.linear()
              .domain(d3.extent(data, getSize))
              .range([sizeMin, sizeMax]);
        model.getSizeScaled = function (d){ return sizeScale(getSize(d)); };
      } else {
        model.getSizeScaled = function (d){ return sizeDefault; };
      }
    });

    // Allow the API client to optionally specify a color column.
    model.colorColumn = None;
    model.colorRange = None;

    // The default color of circles (CSS color string).
    model.colorDefault = "black";

    // Set up the size scale.
    model.when(["colorColumn", "data", "colorDefault", "colorRange"],
        function (colorColumn, data, colorDefault, colorRange){
      if(colorColumn !== None && colorRange !== None){
        var getColor = function (d){ return d[colorColumn] },
            colorScale = d3.scale.ordinal()
              .domain(data.map(getColor))
              .range(colorRange);
        model.getColorScaled = function (d){ return colorScale(getColor(d)); };
      } else {
        model.getColorScaled = function (d){ return colorDefault; };
      }
    });

    // Filter out points that go beyond the edges of the plot
    // for the case that the domain is set explicitly and is
    // smaller than the extent of the data.
    model.when(["data", "getX", "getY", "xScale", "yScale"],
        function(data, getX, getY, xScale, yScale){
      var xMin = xScale.domain()[0], xMax = xScale.domain()[1],
          yMin = yScale.domain()[0], yMax = yScale.domain()[1];
      model.visibleData = data.filter(function(d){
        var x = getX(d), y = getY(d);
        return x > xMin && x < xMax && y > yMin && y < yMax;
      });
    });

    // Draw the circles of the scatter plot.
    model.when(["visibleData", "circlesG", "getXScaled", "getYScaled", "getSizeScaled", "getColorScaled"],
        function (visibleData, circlesG, getXScaled, getYScaled, getSizeScaled, getColorScaled){

      var circles = circlesG.selectAll("circle").data(visibleData);
      circles.enter().append("circle");
      circles
        .attr("cx", getXScaled)
        .attr("cy", getYScaled)
        .attr("r", getSizeScaled)
        .attr("fill", getColorScaled);
      circles.exit().remove();

    });

    // Set defaults at the end so they override optional properties set to None.
    model.set(defaults);

    return model;
  };
});

## styles.css
/* Remove the default margin. */
body {
  margin: 0px;
}

/* Make the visualization container fill the page. */
#container {

  /* Use the default size from bl.ocks.org */
  width: 960px;
  height: 500px;
}

/* Put a border around each plot. */
svg {
  border-style: solid;
  border-color: lightgray;
  border-width: 1px;
}

/* Style the visualization. Draws from http://bl.ocks.org/mbostock/3887118 */

/* Tick mark labels */
.axis .tick text {
  font: 8pt sans-serif;
}

/* Axis labels */
.axis text {
  font: 14pt sans-serif;
}

.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

.line {
  fill: none;
  stroke: black;
  stroke-width: 1.5px;
}

.title-text {
  text-anchor: middle;
  font: 24pt sans-serif;
}

/* Style the brush. Draws from http://bl.ocks.org/mbostock/4343214 */
.brush .extent {
  stroke: gray;
  fill-opacity: .125;
  shape-rendering: crispEdges;
}

## thumbnail.png

      
    Raw
  

              thumbnail.png
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">

	<!-- Use RequireJS for module loading. -->
	<script src="//cdnjs.cloudflare.com/ajax/libs/require.js/2.1.14/require.js"></script>

	<!-- Configure AMD modules. -->
	<script>
	requirejs.config({
	paths: {
	d3: "//d3js.org/d3.v3.min",
	jquery: "//code.jquery.com/jquery-2.1.1.min"
	}
	});
	</script>

	<!-- Include CSS that styles the visualization. -->
	<link rel="stylesheet" href="styles.css">

	<title>Scatter Plot</title>
	</head>
	<body>

	<!-- The visualization will be injected into this div. -->
	<div id="container"></div>

	<!-- Run the main program. -->
	<script src="main.js"></script>

	</body>
	</html>
	{
	"sepal_length":{
	"type": "Q",
	"label": "sepal length (cm)"
	},
	"sepal_width": {
	"type": "Q",
	"label": "sepal width (cm)"
	},
	"petal_length": {
	"type": "Q",
	"label": "petal length (cm)"
	},
	"petal_width": {
	"type": "Q",
	"label": "petal width (cm)"
	},
	"class": {
	"type": "N",
	"label": "species"
	}
	}
sepal_length	sepal_width	petal_length	petal_width	class
5.1	3.5	1.4	0.2	Iris-setosa
4.9	3.0	1.4	0.2	Iris-setosa
4.7	3.2	1.3	0.2	Iris-setosa
4.6	3.1	1.5	0.2	Iris-setosa
5.0	3.6	1.4	0.2	Iris-setosa
5.4	3.9	1.7	0.4	Iris-setosa
4.6	3.4	1.4	0.3	Iris-setosa
5.0	3.4	1.5	0.2	Iris-setosa
4.4	2.9	1.4	0.2	Iris-setosa
4.9	3.1	1.5	0.1	Iris-setosa
5.4	3.7	1.5	0.2	Iris-setosa
4.8	3.4	1.6	0.2	Iris-setosa
4.8	3.0	1.4	0.1	Iris-setosa
4.3	3.0	1.1	0.1	Iris-setosa
5.8	4.0	1.2	0.2	Iris-setosa
5.7	4.4	1.5	0.4	Iris-setosa
5.4	3.9	1.3	0.4	Iris-setosa
5.1	3.5	1.4	0.3	Iris-setosa
5.7	3.8	1.7	0.3	Iris-setosa
5.1	3.8	1.5	0.3	Iris-setosa
5.4	3.4	1.7	0.2	Iris-setosa
5.1	3.7	1.5	0.4	Iris-setosa
4.6	3.6	1.0	0.2	Iris-setosa
5.1	3.3	1.7	0.5	Iris-setosa
4.8	3.4	1.9	0.2	Iris-setosa
5.0	3.0	1.6	0.2	Iris-setosa
5.0	3.4	1.6	0.4	Iris-setosa
5.2	3.5	1.5	0.2	Iris-setosa
5.2	3.4	1.4	0.2	Iris-setosa
4.7	3.2	1.6	0.2	Iris-setosa
4.8	3.1	1.6	0.2	Iris-setosa
5.4	3.4	1.5	0.4	Iris-setosa
5.2	4.1	1.5	0.1	Iris-setosa
5.5	4.2	1.4	0.2	Iris-setosa
4.9	3.1	1.5	0.1	Iris-setosa
5.0	3.2	1.2	0.2	Iris-setosa
5.5	3.5	1.3	0.2	Iris-setosa
4.9	3.1	1.5	0.1	Iris-setosa
4.4	3.0	1.3	0.2	Iris-setosa
5.1	3.4	1.5	0.2	Iris-setosa
5.0	3.5	1.3	0.3	Iris-setosa
4.5	2.3	1.3	0.3	Iris-setosa
4.4	3.2	1.3	0.2	Iris-setosa
5.0	3.5	1.6	0.6	Iris-setosa
5.1	3.8	1.9	0.4	Iris-setosa
4.8	3.0	1.4	0.3	Iris-setosa
5.1	3.8	1.6	0.2	Iris-setosa
4.6	3.2	1.4	0.2	Iris-setosa
5.3	3.7	1.5	0.2	Iris-setosa
5.0	3.3	1.4	0.2	Iris-setosa
7.0	3.2	4.7	1.4	Iris-versicolor
6.4	3.2	4.5	1.5	Iris-versicolor
6.9	3.1	4.9	1.5	Iris-versicolor
5.5	2.3	4.0	1.3	Iris-versicolor
6.5	2.8	4.6	1.5	Iris-versicolor
5.7	2.8	4.5	1.3	Iris-versicolor
6.3	3.3	4.7	1.6	Iris-versicolor
4.9	2.4	3.3	1.0	Iris-versicolor
6.6	2.9	4.6	1.3	Iris-versicolor
5.2	2.7	3.9	1.4	Iris-versicolor
5.0	2.0	3.5	1.0	Iris-versicolor
5.9	3.0	4.2	1.5	Iris-versicolor
6.0	2.2	4.0	1.0	Iris-versicolor
6.1	2.9	4.7	1.4	Iris-versicolor
5.6	2.9	3.6	1.3	Iris-versicolor
6.7	3.1	4.4	1.4	Iris-versicolor
5.6	3.0	4.5	1.5	Iris-versicolor
5.8	2.7	4.1	1.0	Iris-versicolor
6.2	2.2	4.5	1.5	Iris-versicolor
5.6	2.5	3.9	1.1	Iris-versicolor
5.9	3.2	4.8	1.8	Iris-versicolor
6.1	2.8	4.0	1.3	Iris-versicolor
6.3	2.5	4.9	1.5	Iris-versicolor
6.1	2.8	4.7	1.2	Iris-versicolor
6.4	2.9	4.3	1.3	Iris-versicolor
6.6	3.0	4.4	1.4	Iris-versicolor
6.8	2.8	4.8	1.4	Iris-versicolor
6.7	3.0	5.0	1.7	Iris-versicolor
6.0	2.9	4.5	1.5	Iris-versicolor
5.7	2.6	3.5	1.0	Iris-versicolor
5.5	2.4	3.8	1.1	Iris-versicolor
5.5	2.4	3.7	1.0	Iris-versicolor
5.8	2.7	3.9	1.2	Iris-versicolor
6.0	2.7	5.1	1.6	Iris-versicolor
5.4	3.0	4.5	1.5	Iris-versicolor
6.0	3.4	4.5	1.6	Iris-versicolor
6.7	3.1	4.7	1.5	Iris-versicolor
6.3	2.3	4.4	1.3	Iris-versicolor
5.6	3.0	4.1	1.3	Iris-versicolor
5.5	2.5	4.0	1.3	Iris-versicolor
5.5	2.6	4.4	1.2	Iris-versicolor
6.1	3.0	4.6	1.4	Iris-versicolor
5.8	2.6	4.0	1.2	Iris-versicolor
5.0	2.3	3.3	1.0	Iris-versicolor
5.6	2.7	4.2	1.3	Iris-versicolor
5.7	3.0	4.2	1.2	Iris-versicolor
5.7	2.9	4.2	1.3	Iris-versicolor
6.2	2.9	4.3	1.3	Iris-versicolor
5.1	2.5	3.0	1.1	Iris-versicolor
5.7	2.8	4.1	1.3	Iris-versicolor
6.3	3.3	6.0	2.5	Iris-virginica
5.8	2.7	5.1	1.9	Iris-virginica
7.1	3.0	5.9	2.1	Iris-virginica
6.3	2.9	5.6	1.8	Iris-virginica
6.5	3.0	5.8	2.2	Iris-virginica
7.6	3.0	6.6	2.1	Iris-virginica
4.9	2.5	4.5	1.7	Iris-virginica
7.3	2.9	6.3	1.8	Iris-virginica
6.7	2.5	5.8	1.8	Iris-virginica
7.2	3.6	6.1	2.5	Iris-virginica
6.5	3.2	5.1	2.0	Iris-virginica
6.4	2.7	5.3	1.9	Iris-virginica
6.8	3.0	5.5	2.1	Iris-virginica
5.7	2.5	5.0	2.0	Iris-virginica
5.8	2.8	5.1	2.4	Iris-virginica
6.4	3.2	5.3	2.3	Iris-virginica
6.5	3.0	5.5	1.8	Iris-virginica
7.7	3.8	6.7	2.2	Iris-virginica
7.7	2.6	6.9	2.3	Iris-virginica
6.0	2.2	5.0	1.5	Iris-virginica
6.9	3.2	5.7	2.3	Iris-virginica
5.6	2.8	4.9	2.0	Iris-virginica
7.7	2.8	6.7	2.0	Iris-virginica
6.3	2.7	4.9	1.8	Iris-virginica
6.7	3.3	5.7	2.1	Iris-virginica
7.2	3.2	6.0	1.8	Iris-virginica
6.2	2.8	4.8	1.8	Iris-virginica
6.1	3.0	4.9	1.8	Iris-virginica
6.4	2.8	5.6	2.1	Iris-virginica
7.2	3.0	5.8	1.6	Iris-virginica
7.4	2.8	6.1	1.9	Iris-virginica
7.9	3.8	6.4	2.0	Iris-virginica
6.4	2.8	5.6	2.2	Iris-virginica
6.3	2.8	5.1	1.5	Iris-virginica
6.1	2.6	5.6	1.4	Iris-virginica
7.7	3.0	6.1	2.3	Iris-virginica
6.3	3.4	5.6	2.4	Iris-virginica
6.4	3.1	5.5	1.8	Iris-virginica
6.0	3.0	4.8	1.8	Iris-virginica
6.9	3.1	5.4	2.1	Iris-virginica
6.7	3.1	5.6	2.4	Iris-virginica
6.9	3.1	5.1	2.3	Iris-virginica
5.8	2.7	5.1	1.9	Iris-virginica
6.8	3.2	5.9	2.3	Iris-virginica
6.7	3.3	5.7	2.5	Iris-virginica
6.7	3.0	5.2	2.3	Iris-virginica
6.3	2.5	5.0	1.9	Iris-virginica
6.5	3.0	5.2	2.0	Iris-virginica
6.2	3.4	5.4	2.3	Iris-virginica
5.9	3.0	5.1	1.8	Iris-virginica
	// This is the main program that sets up a scatter plot to visualize the Iris data set.
	// Curran Kelleher March 2015
	require(["scatterPlot"], function (ScatterPlot) {

	// Initialize the scatter plot.
	var options = {

	// Tell the visualization which DOM element to insert itself into.
	container: d3.select("#container").node(),

	// Specify the margin and text label offsets.
	margin: {
	top: 10,
	right: 10,
	bottom: 45,
	left: 55
	},
	yAxisLabelOffset: 1.8, // Unit is CSS "em"s
	xAxisLabelOffset: 1.9,
	titleOffset: 0.3
	},
	scatterPlot1 = ScatterPlot(options),
	scatterPlot2 = ScatterPlot(options);

	// Fetch the column metadata.
	d3.json("iris-metadata.json", function (metadata) {

	var xColumn = "sepal_length",
	yColumn = "petal_length",
	sizeColumn = "petal_width",
	colorColumn = "class",
	xyOptions = {
	xColumn: xColumn,
	xAxisLabel: metadata[xColumn].label,
	yColumn: yColumn,
	yAxisLabel: metadata[yColumn].label
	};

	// Use the same X and Y for all plots.
	scatterPlot1.set(xyOptions);
	scatterPlot2.set(xyOptions);

	// Load the data from a CSV file.
	d3.csv("iris.csv", function (data){

	// Parse quantitative values from strings to numbers.
	var quantitativeColumns = Object.keys(metadata).filter(function (column){
	return metadata[column].type === "Q";
	});
	data.forEach(function (d){
	quantitativeColumns.forEach(function (column){
	d[column] = parseFloat(d[column]);
	});
	});

	// Pass the data into the plots.
	scatterPlot1.data = data;
	scatterPlot2.data = data;
	});

	// Use the first plot to zoom in the second plot.
	scatterPlot1.brushEnabled = true;
	scatterPlot1.when("brushedIntervals", function (brushedIntervals){
	scatterPlot2.xDomainMin = brushedIntervals[xColumn][0];
	scatterPlot2.xDomainMax = brushedIntervals[xColumn][1];
	scatterPlot2.yDomainMin = brushedIntervals[yColumn][0];
	scatterPlot2.yDomainMax = brushedIntervals[yColumn][1];
	});

	// Initialize the default brush.
	scatterPlot1.brushedIntervals = {
	"sepal_length": [ 4.82, 7.77 ],
	"petal_length": [ 2.84, 6.80 ]
	};
	});

	// Sets the `box` model property
	// based on the size of the container,
	function computeBoxes(){
	var width = container.clientWidth,
	height = container.clientHeight,
	padding = 10,
	plotWidth = (width - padding * 2) / 2,
	plotHeight = height - padding * 2;
	scatterPlot1.box = {
	x: padding,
	y: padding,
	width: plotWidth,
	height: plotHeight
	};
	scatterPlot2.box = {
	x: plotWidth + padding * 2,
	y: padding,
	width: plotWidth,
	height: plotHeight
	};
	}

	// once to initialize `model.box`, and
	computeBoxes();

	// whenever the browser window resizes in the future.
	window.addEventListener("resize", computeBoxes);
	});
	// A functional reactive model library.
	//
	(function(){

	// The D3 conventional graph representation.
	// See https://github.com/mbostock/d3/wiki/Force-Layout#nodes
	var nodes, links, idCounter, map;

	function resetFlowGraph(){
	nodes = [];
	links = [];
	idCounter = 0;
	map = {};
	}

	function getFlowGraph(){
	return {
	nodes: nodes,
	links: links
	};
	}

	resetFlowGraph();

	// Adds the nodes and links to the data flow graph for one
	// particular reactive function.
	function updateLambda(modelId, lambdaId, inProperties, outProperties){
	var lambda = lambdaNode(lambdaId);
	inProperties.forEach(function(property){
	link(propertyNode(modelId, property), lambda);
	});
	outProperties.forEach(function(property){
	link(lambda, propertyNode(modelId, property));
	});
	}

	function lambdaNode(id){
	return getOrCreate(id, nodes, createLambda);
	}

	function createLambda(index){
	return {
	type: "lambda",
	index: index
	};
	}

	function propertyNode(modelId, property){
	var id = modelId + "." + property;
	return getOrCreate(id, nodes, createPropertyNode(property));
	}

	function createPropertyNode(property){
	return function(index){
	return {
	type: "property",
	index: index,
	property: property
	};
	};
	}

	function link(sourceNode, targetNode){
	var source = sourceNode.index,
	target = targetNode.index,
	id = source + "-" + target;
	getOrCreate(id, links, createLink(source, target));
	}

	function createLink(source, target){
	return function(index){
	return {
	source: source,
	target: target
	};
	};
	}

	function getOrCreate(id, things, createThing){
	var thing = map[id];
	if(!thing){
	thing = map[id] = createThing(things.length);
	things.push(thing);
	}
	return thing;
	}

	// The constructor function, accepting default values.
	function Model(defaults){

	// The returned public API object.
	var model = {},

	// The internal stored values for tracked properties. { property -> value }
	values = {},

	// The callback functions for each tracked property. { property -> [callback] }
	listeners = {},

	// The set of tracked properties. { property -> true }
	trackedProperties = {},

	modelId = idCounter++,
	changedProperties = {};

	// The functional reactive "when" operator.
	//
	// * `properties` An array of property names (can also be a single property string).
	// * `callback` A callback function that is called:
	// * with property values as arguments, ordered corresponding to the properties array,
	// * only if all specified properties have values,
	// * once for initialization,
	// * whenever one or more specified properties change,
	// * on the next tick of the JavaScript event loop after properties change,
	// * only once as a result of one or more synchronous changes to dependency properties.
	function when(properties, callback, thisArg){

	var lambdaId = idCounter++;

	// Make sure the default `this` becomes
	// the object you called `.on` on.
	thisArg = thisArg \|\| this;

	// Handle either an array or a single string.
	properties = (properties instanceof Array) ? properties : [properties];

	// This function will trigger the callback to be invoked.
	var triggerCallback = debounce(function (){
	var args = properties.map(function(property){
	return values[property];
	});
	if(allAreDefined(args)){
	changedProperties = {};

	callback.apply(thisArg, args);

	updateLambda(modelId, lambdaId, properties, Object.keys(changedProperties));
	}
	});

	// Trigger the callback once for initialization.
	triggerCallback();

	// Trigger the callback whenever specified properties change.
	properties.forEach(function(property){
	on(property, triggerCallback);
	});

	// Return this function so it can be removed later.
	return triggerCallback;
	}

	// Returns a debounced version of the given function.
	// See http://underscorejs.org/#debounce
	function debounce(callback){
	var queued = false;
	return function () {
	if(!queued){
	queued = true;
	setTimeout(function () {
	queued = false;
	callback();
	}, 0);
	}
	};
	}

	// Returns true if all elements of the given array are defined, false otherwise.
	function allAreDefined(arr){
	return !arr.some(function (d) {
	return typeof d === 'undefined' \|\| d === null;
	});
	}

	// Adds a change listener for a given property with Backbone-like behavior.
	// Similar to http://backbonejs.org/#Events-on
	function on(property, callback, thisArg){

	// Make sure the default `this` becomes
	// the object you called `.on` on.
	thisArg = thisArg \|\| this;
	getListeners(property).push(callback);
	track(property, thisArg);
	}

	// Gets or creates the array of listener functions for a given property.
	function getListeners(property){
	return listeners[property] \|\| (listeners[property] = []);
	}

	// Tracks a property if it is not already tracked.
	function track(property, thisArg){
	if(!(property in trackedProperties)){
	trackedProperties[property] = true;
	values[property] = model[property];
	Object.defineProperty(model, property, {
	get: function () { return values[property]; },
	set: function(newValue) {
	var oldValue = values[property];
	values[property] = newValue;
	getListeners(property).forEach(function(callback){
	callback.call(thisArg, newValue, oldValue);
	});

	changedProperties[property] = true;
	}
	});
	}
	}

	// Removes a listener added using `when()`.
	function cancel(listener){
	for(var property in listeners){
	off(property, listener);
	}
	}

	// Removes a change listener added using `on`.
	function off(property, callback){
	listeners[property] = listeners[property].filter(function (listener) {
	return listener !== callback;
	});
	}

	// Sets all of the given values on the model.
	// `newValues` is an object { property -> value }.
	function set(newValues){
	for(var property in newValues){
	model[property] = newValues[property];
	}
	}

	// Transfer defaults passed into the constructor to the model.
	set(defaults);

	// Expose the public API.
	model.when = when;
	model.cancel = cancel;
	model.on = on;
	model.off = off;
	model.set = set;
	return model;
	}

	Model.getFlowGraph = getFlowGraph;
	Model.resetFlowGraph = resetFlowGraph;

	// Support AMD (RequireJS), CommonJS (Node), and browser globals.
	// Inspired by https://github.com/umdjs/umd
	if (typeof define === "function" && define.amd) {
	define([], function () { return Model; });
	} else if (typeof exports === "object") {
	module.exports = Model;
	} else {
	this.Model = Model;
	}
	})();
	// A reusable scatter plot module.
	// Curran Kelleher March 2015
	define(["d3", "model"], function (d3, Model) {

	// A representation for an optional Model property that is not specified.
	// This allows the "when" approach to support optional properties.
	// Inspired by Scala's Option type.
	// See http://alvinalexander.com/scala/using-scala-option-some-none-idiom-function-java-null
	var None = "__none__";

	// The constructor function, accepting default values.
	return function ScatterPlot(defaults) {

	// Create a Model instance for the visualization.
	// This will serve as its public API.
	var model = Model();

	// Create an SVG element from the container DOM element.
	model.when("container", function (container) {
	model.svg = d3.select(container).append("svg")

	// Use CSS `position: absolute;`
	// so setting `left` and `top` later will
	// position the SVG relative to the container div.
	.style("position", "absolute");
	});

	// Adjust the size of the SVG based on the `box` property.
	model.when(["svg", "box"], function (svg, box) {

	// Set the CSS `left` and `top` properties
	// to move the SVG to `(box.x, box.y)`
	// relative to the container div.
	svg
	.style("left", box.x + "px")
	.style("top", box.y + "px")
	.attr("width", box.width)
	.attr("height", box.height);
	});

	// Create an SVG group that will contain the visualization.
	model.when("svg", function (svg) {
	model.g = svg.append("g");
	});

	model.when("g", function (g) {

	// Add an SVG group to contain the marks.
	model.circlesG = g.append("g");

	// Create a group for the brush.
	model.brushG = g.append("g").attr("class", "brush");

	// The circles group is added first, before the brush group,
	// so that mouse events go to the brush rather than to the
	// circles, even when the mouse is on top of a circle.
	});

	// Disable brushing by default.
	model.brushEnabled = false;

	// Set up brushing interactions to define `brushedIntervals` on the model.
	model.when(["brushEnabled", "xColumn", "yColumn", "xScale", "yScale"],
	function (brushEnabled, xColumn, yColumn, xScale, yScale) {
	if(brushEnabled){
	var brush = d3.svg.brush();
	brush.on("brush", function () {
	model.brushedIntervals = brushToIntervals(brush, xColumn, yColumn, xScale, yScale);
	});
	model.brush = brush;
	}
	});


	function brushToIntervals(brush, xColumn, yColumn, xScale, yScale){
	var brushedIntervals = {};
	if(!brush.empty()
	&& brush.extent() !== null){
	var e = brush.extent(),
	xMin = e[0][0],
	yMin = e[0][1],
	xMax = e[1][0],
	yMax = e[1][1],
	epsilon = 0.01;

	// Account for the edge case where the brush is at the
	// X or Y min or max. Adding a small value ensures that all
	// points are included when crossfilter's filterRange is used,
	// because filterRange provides an exclusive range, not inclusive.
	// See https://github.com/square/crossfilter/wiki/API-Reference#dimension_filterRange
	if(xMax === xScale.domain()[1]){ xMax += epsilon; }
	if(yMax === yScale.domain()[1]){ yMax += epsilon; }
	if(xMin === xScale.domain()[0]){ xMin -= epsilon; }
	if(yMin === yScale.domain()[0]){ yMin -= epsilon; }

	brushedIntervals[xColumn] = [xMin, xMax];
	brushedIntervals[yColumn] = [yMin, yMax];
	} else {
	brushedIntervals[xColumn] = [None, None];
	brushedIntervals[yColumn] = [None, None];
	}
	return brushedIntervals;
	}

	function intervalsToBrush(brushedIntervals, xColumn, yColumn){
	return [
	[brushedIntervals[xColumn][0], brushedIntervals[yColumn][0]],
	[brushedIntervals[xColumn][1], brushedIntervals[yColumn][1]]
	];
	}

	// Update the rendered brush.
	model.when(["brushedIntervals", "brush", "brushG", "xColumn", "yColumn", "xScale", "yScale"],
	function (brushedIntervals, brush, brushG, xColumn, yColumn, xScale, yScale) {

	// Update the scales within the brush.
	brush.x(xScale);
	brush.y(yScale);

	// Update the extent of the brush.
	brush.extent(intervalsToBrush(brushedIntervals, xColumn, yColumn));

	// Render the brush onto the brush group.
	brushG.call(brush);
	});

	// Adjust the SVG group translation based on the margin.
	model.when(["g", "margin"], function (g, margin) {
	g.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
	});

	// Create the title text element.
	model.when("g", function (g){
	model.titleText = g.append("text").attr("class", "title-text");
	});

	// Center the title text when width changes.
	model.when(["titleText", "width"], function (titleText, width) {
	titleText.attr("x", width / 2);
	});

	// Update the title text based on the `title` property.
	model.when(["titleText", "title"], function (titleText, title){
	titleText.text(title);
	});

	// Update the title text offset.
	model.when(["titleText", "titleOffset"], function (titleText, titleOffset){
	titleText.attr("dy", titleOffset + "em");
	});

	// Compute the inner box from the outer box and margin.
	// See Margin Convention http://bl.ocks.org/mbostock/3019563
	model.when(["box", "margin"], function (box, margin) {
	model.width = box.width - margin.left - margin.right;
	model.height = box.height - margin.top - margin.bottom;
	});

	// Generate a function for getting the X value.
	model.when(["data", "xColumn"], function (data, xColumn) {
	model.getX = function (d) { return d[xColumn]; };
	});

	// Compute the domain of the X attribute.

	// Allow the API client to optionally specify fixed min and max values.
	model.xDomainMin = None;
	model.xDomainMax = None;
	model.when(["data", "getX", "xDomainMin", "xDomainMax"],
	function (data, getX, xDomainMin, xDomainMax) {

	if(xDomainMin === None && xDomainMax === None){
	model.xDomain = d3.extent(data, getX);
	} else {
	if(xDomainMin === None){
	xDomainMin = d3.min(data, getX);
	}
	if(xDomainMax === None){
	xDomainMax = d3.max(data, getX);
	}
	model.xDomain = [xDomainMin, xDomainMax]
	}
	});

	// Compute the X scale.
	model.when(["xDomain", "width"], function (xDomain, width) {
	model.xScale = d3.scale.linear().domain(xDomain).range([0, width]);
	});

	// Generate a function for getting the scaled X value.
	model.when(["data", "xScale", "getX"], function (data, xScale, getX) {
	model.getXScaled = function (d) { return xScale(getX(d)); };
	});

	// Set up the X axis.
	model.when("g", function (g) {
	model.xAxisG = g.append("g").attr("class", "x axis");
	model.xAxisText = model.xAxisG.append("text").style("text-anchor", "middle");
	});

	// Move the X axis label based on its specified offset.
	model.when(["xAxisText", "xAxisLabelOffset"], function (xAxisText, xAxisLabelOffset){
	xAxisText.attr("dy", xAxisLabelOffset + "em");
	});

	// Update the X axis transform when height changes.
	model.when(["xAxisG", "height"], function (xAxisG, height) {
	xAxisG.attr("transform", "translate(0," + height + ")");
	});

	// Center the X axis label when width changes.
	model.when(["xAxisText", "width"], function (xAxisText, width) {
	xAxisText.attr("x", width / 2);
	});

	// Update the X axis based on the X scale.
	model.when(["xAxisG", "xScale"], function (xAxisG, xScale) {
	xAxisG.call(d3.svg.axis().orient("bottom").scale(xScale));
	});

	// Update X axis label.
	model.when(["xAxisText", "xAxisLabel"], function (xAxisText, xAxisLabel) {
	xAxisText.text(xAxisLabel);
	});

	// Generate a function for getting the Y value.
	model.when(["data", "yColumn"], function (data, yColumn) {
	model.getY = function (d) { return d[yColumn]; };
	});

	// Compute the domain of the Y attribute.

	// Allow the API client to optionally specify fixed min and max values.
	model.yDomainMin = None;
	model.yDomainMax = None;
	model.when(["data", "getY", "yDomainMin", "yDomainMax"],
	function (data, getY, yDomainMin, yDomainMax) {

	if(yDomainMin === None && yDomainMax === None){
	model.yDomain = d3.extent(data, getY);
	} else {
	if(yDomainMin === None){
	yDomainMin = d3.min(data, getY);
	}
	if(yDomainMax === None){
	yDomainMax = d3.max(data, getY);
	}
	model.yDomain = [yDomainMin, yDomainMax]
	}
	});

	// Compute the Y scale.
	model.when(["data", "yDomain", "height"], function (data, yDomain, height) {
	model.yScale = d3.scale.linear().domain(yDomain).range([height, 0]);
	});

	// Generate a function for getting the scaled Y value.
	model.when(["data", "yScale", "getY"], function (data, yScale, getY) {
	model.getYScaled = function (d) { return yScale(getY(d)); };
	});

	// Set up the Y axis.
	model.when("g", function (g) {
	model.yAxisG = g.append("g").attr("class", "y axis");
	model.yAxisText = model.yAxisG.append("text")
	.style("text-anchor", "middle")
	.attr("transform", "rotate(-90)")
	.attr("y", 0);
	});

	// Move the Y axis label based on its specified offset.
	model.when(["yAxisText", "yAxisLabelOffset"], function (yAxisText, yAxisLabelOffset){
	yAxisText.attr("dy", "-" + yAxisLabelOffset + "em")
	});

	// Center the Y axis label when height changes.
	model.when(["yAxisText", "height"], function (yAxisText, height) {
	yAxisText.attr("x", -height / 2);
	});

	// Update Y axis label.
	model.when(["yAxisText", "yAxisLabel"], function (yAxisText, yAxisLabel) {
	yAxisText.text(yAxisLabel);
	});

	// Update the Y axis based on the Y scale.
	model.when(["yAxisG", "yScale"], function (yAxisG, yScale) {
	yAxisG.call(d3.svg.axis().orient("left").scale(yScale));
	});

	// Allow the API client to optionally specify a size column.
	model.sizeColumn = None;

	// The default radius of circles in pixels.
	model.sizeDefault = 2;

	// The min and max circle radius in pixels.
	model.sizeMin = 0.5;
	model.sizeMax = 6;

	// Set up the size scale.
	model.when(["sizeColumn", "data", "sizeDefault", "sizeMin", "sizeMax"],
	function (sizeColumn, data, sizeDefault, sizeMin, sizeMax){
	if(sizeColumn !== None){
	var getSize = function (d){ return d[sizeColumn] },
	sizeScale = d3.scale.linear()
	.domain(d3.extent(data, getSize))
	.range([sizeMin, sizeMax]);
	model.getSizeScaled = function (d){ return sizeScale(getSize(d)); };
	} else {
	model.getSizeScaled = function (d){ return sizeDefault; };
	}
	});

	// Allow the API client to optionally specify a color column.
	model.colorColumn = None;
	model.colorRange = None;

	// The default color of circles (CSS color string).
	model.colorDefault = "black";

	// Set up the size scale.
	model.when(["colorColumn", "data", "colorDefault", "colorRange"],
	function (colorColumn, data, colorDefault, colorRange){
	if(colorColumn !== None && colorRange !== None){
	var getColor = function (d){ return d[colorColumn] },
	colorScale = d3.scale.ordinal()
	.domain(data.map(getColor))
	.range(colorRange);
	model.getColorScaled = function (d){ return colorScale(getColor(d)); };
	} else {
	model.getColorScaled = function (d){ return colorDefault; };
	}
	});

	// Filter out points that go beyond the edges of the plot
	// for the case that the domain is set explicitly and is
	// smaller than the extent of the data.
	model.when(["data", "getX", "getY", "xScale", "yScale"],
	function(data, getX, getY, xScale, yScale){
	var xMin = xScale.domain()[0], xMax = xScale.domain()[1],
	yMin = yScale.domain()[0], yMax = yScale.domain()[1];
	model.visibleData = data.filter(function(d){
	var x = getX(d), y = getY(d);
	return x > xMin && x < xMax && y > yMin && y < yMax;
	});
	});

	// Draw the circles of the scatter plot.
	model.when(["visibleData", "circlesG", "getXScaled", "getYScaled", "getSizeScaled", "getColorScaled"],
	function (visibleData, circlesG, getXScaled, getYScaled, getSizeScaled, getColorScaled){

	var circles = circlesG.selectAll("circle").data(visibleData);
	circles.enter().append("circle");
	circles
	.attr("cx", getXScaled)
	.attr("cy", getYScaled)
	.attr("r", getSizeScaled)
	.attr("fill", getColorScaled);
	circles.exit().remove();

	});

	// Set defaults at the end so they override optional properties set to None.
	model.set(defaults);

	return model;
	};
	});
	/* Remove the default margin. */
	body {
	margin: 0px;
	}

	/* Make the visualization container fill the page. */
	#container {

	/* Use the default size from bl.ocks.org */
	width: 960px;
	height: 500px;
	}

	/* Put a border around each plot. */
	svg {
	border-style: solid;
	border-color: lightgray;
	border-width: 1px;
	}

	/* Style the visualization. Draws from http://bl.ocks.org/mbostock/3887118 */

	/* Tick mark labels */
	.axis .tick text {
	font: 8pt sans-serif;
	}

	/* Axis labels */
	.axis text {
	font: 14pt sans-serif;
	}

	.axis path,
	.axis line {
	fill: none;
	stroke: #000;
	shape-rendering: crispEdges;
	}

	.line {
	fill: none;
	stroke: black;
	stroke-width: 1.5px;
	}

	.title-text {
	text-anchor: middle;
	font: 24pt sans-serif;
	}

	/* Style the brush. Draws from http://bl.ocks.org/mbostock/4343214 */
	.brush .extent {
	stroke: gray;
	fill-opacity: .125;
	shape-rendering: crispEdges;
	}