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Treemaps

Overview

A visual representation of a data tree, where each node can have zero or more children, and one parent (except for the root, which has no parents). Each node is displayed as a rectangle, sized and colored according to values that you assign. Sizes and colors are valued relative to all other nodes in the graph. You can specify how many levels to display simultaneously, and optionally to display deeper levels in a hinted fashion. If a node is a leaf node, you can specify a size and color; if it is not a leaf, it will be displayed as a bounding box for leaf nodes. The default behavior is to move down the tree when a user left-clicks a node, and to move back up the tree when a user right-clicks the graph.

The total size of the graph is determined by the size of the containing element that you insert in your page. If you have leaf nodes with names too long to show, the name will be truncated with an ellipsis (...).

Example

<html>
  <head>
    <script type="text/javascript" src="https://www.google.com/jsapi"></script>
    <script type="text/javascript">
      google.load("visualization", "1", {packages:["treemap"]});
      google.setOnLoadCallback(drawChart);
      function drawChart() {
        var data = google.visualization.arrayToDataTable([
          ['Location', 'Parent', 'Market trade volume (size)', 'Market increase/decrease (color)'],
          ['Global',    null,                 0,                               0],
          ['America',   'Global',             0,                               0],
          ['Europe',    'Global',             0,                               0],
          ['Asia',      'Global',             0,                               0],
          ['Australia', 'Global',             0,                               0],
          ['Africa',    'Global',             0,                               0],
          ['Brazil',    'America',            11,                              10],
          ['USA',       'America',            52,                              31],
          ['Mexico',    'America',            24,                              12],
          ['Canada',    'America',            16,                              -23],
          ['France',    'Europe',             42,                              -11],
          ['Germany',   'Europe',             31,                              -2],
          ['Sweden',    'Europe',             22,                              -13],
          ['Italy',     'Europe',             17,                              4],
          ['UK',        'Europe',             21,                              -5],
          ['China',     'Asia',               36,                              4],
          ['Japan',     'Asia',               20,                              -12],
          ['India',     'Asia',               40,                              63],
          ['Laos',      'Asia',               4,                               34],
          ['Mongolia',  'Asia',               1,                               -5],
          ['Israel',    'Asia',               12,                              24],
          ['Iran',      'Asia',               18,                              13],
          ['Pakistan',  'Asia',               11,                              -52],
          ['Egypt',     'Africa',             21,                              0],
          ['S. Africa', 'Africa',             30,                              43],
          ['Sudan',     'Africa',             12,                              2],
          ['Congo',     'Africa',             10,                              12],
          ['Zaire',     'Africa',             8,                               10]
        ]);

        tree = new google.visualization.TreeMap(document.getElementById('chart_div'));

        tree.draw(data, {
          minColor: '#f00',
          midColor: '#ddd',
          maxColor: '#0d0',
          headerHeight: 15,
          fontColor: 'black',
          showScale: true
        });

      }
    </script>
  </head>
  <body>
    <div id="chart_div" style="width: 900px; height: 500px;"></div>
  </body>
</html>

Highlights

You can specify whether elements should highlight when moused over, and set specific colors for certain elements to use when this occurs. To turn on highlighting, set highlightOnMouseOver: true. From there, you can set your colors to use for highlighting elements using the various HighlightColor options.

      var options = {
        highlightOnMouseOver: true,
        maxDepth: 1,
        maxPostDepth: 2,
        minHighlightColor: '#8c6bb1',
        midHighlightColor: '#9ebcda',
        maxHighlightColor: '#edf8fb',
        minColor: '#009688',
        midColor: '#f7f7f7',
        maxColor: '#ee8100',
        headerHeight: 15,
        showScale: true,
        height: 500,
        useWeightedAverageForAggregation: true
      };

Tooltips

By default, treemap tooltips are basic, showing the label of the treemap cell. This is useful when the cells are too small to contain the labels, but you can customize them further as described in this section.

Treemap tooltips are customized differently than other charts: you define a function and then set the generateTooltip option to that function. Here's a simple example:

In the above chart, we define a function called showStaticTooltip that simply returns a string with the HTML to be shown whenever the user hovers over a treemap cell. Try it! The code to generate that is as follows:

  var options = {
    minColor: '#e7711c',
    midColor: '#fff',
    maxColor: '#4374e0',
    showScale: true,
    generateTooltip: showStaticTooltip
  };

  tree.draw(data, options);

  function showStaticTooltip(row, size, value) {
    return '<div style="background:#fd9; padding:10px; border-style:solid">' +
           'Read more about the <a href="http://en.wikipedia.org/wiki/Kingdom_(biology)">kingdoms of life</a>.</div>';
  }

The generateTooltip function can be any JavaScript you like. Usually, you'll want tooltips that vary based on the data values. The following example shows how to access every field in the datatable.

If you hover over the cells in the above treemap, you'll see a different tooltip for each cell. The treemap tooltip functions all take three values: row, size, and value.

  • row: the cell's row from the datatable
  • size: the sum of the value (column 3) of this cell and all its children
  • value: the color of the cell, expressed as a number from 0 to 1

In showFullTooltip, the string we return is an HTML box with five lines:

  • Line 1 shows the appropriate row from the datatable, making liberal use of data.getValue.
  • Line 2 tells you which row that is, which is just the row parameter.
  • Line 3 gives you information from column 3 of the datatable: the sum of the value of column 3 from this row, plus the values from descendants.
  • Line 4 gives you information from column 4 of the datatable. It's the value, but expressed as a number between 0 and 1 corresponding to the color of the cell.
  var options = {
    minColor: '#e7711c',
    midColor: '#fff',
    maxColor: '#4374e0',
    showScale: true,
    generateTooltip: showFullTooltip
  };

  tree.draw(data, options);

  function showFullTooltip(row, size, value) {
    return '<div style="background:#fd9; padding:10px; border-style:solid">' +
           '<span style="font-family:Courier"><b>' + data.getValue(row, 0) +
           '</b>, ' + data.getValue(row, 1) + ', ' + data.getValue(row, 2) +
           ', ' + data.getValue(row, 3) + '</span><br>' +
           'Datatable row: ' + row + '<br>' +
	   data.getColumnLabel(2) +
           ' (total value of this cell and its children): ' + size + '<br>' +
	   data.getColumnLabel(3) + ': ' + value + ' </div>';
  }

}

Loading

The google.load package name is "treemap".

  google.load("visualization", "1", {packages: ["treemap"]});

The visualization's class name is google.visualization.TreeMap.

  var visualization = new google.visualization.TreeMap(container);

Data Format

Each row in the data table describes one node (a rectangle in the graph). Each node (except the root node) has one or more parent nodes. Each node is sized and colored according to its values relative to the other nodes currently shown.

The data table should have four columns in the following format:

  • Column 0 - [string] An ID for this node. It can be any valid JavaScript string, including spaces, and any length that a string can hold. This value is displayed as the node header.
  • Column 1 - [string] - The ID of the parent node. If this is a root node, leave this blank. Only one root is allowed per treemap.
  • Column 2 - [number] - The size of the node. Any positive value is allowed. This value determines the size of the node, computed relative to all other nodes currently shown. For non-leaf nodes, this value is ignored and calculated from the size of all its children.
  • Column 3 - [optional, number] - An optional value used to calculate a color for this node. Any value, positive or negative, is allowed. The color value is first recomputed on a scale from minColorValue to maxColorValue, and then the node is assigned a color from the gradient between minColor and maxColor.

Configuration Options

Name
fontColor

The text color. Specify an HTML color value.

Type: string
Default: #ffffff
fontFamily

The font family to use for all text.

Type: string
Default: auto
fontSize

The font size for all text, in points.

Type: number
Default: 12
forceIFrame

Draws the chart inside an inline frame. (Note that on IE8, this option is ignored; all IE8 charts are drawn in i-frames.)

Type: boolean
Default: false
headerColor

The color of the header section for each node. Specify an HTML color value.

Type: string
Default: #988f86
headerHeight

The height of the header section for each node, in pixels (can be zero).

Type number
Default: 0
headerHighlightColor

The color of the header of a node being hovered over. Specify an HTML color value or null; if null this value will be headerColor lightened by 35%.

Type: string
Default: null
highlightOnMouseOver

Determines if elements should show highlighted effects when moused over. If set to true, highlighting for different elements can be specified using the various highlightColor options.

Type: boolean
Default: false
hintOpacity

When maxPostDepth is greater than 1, causing nodes below the current depth to be shown, hintOpacity specifies how transparent it should be. It should be between 0 and 1; the higher the value, the fainter the node.

Type: number
Default: 0.0
maxColor

The color for a rectangle with a column 3 value of maxColorValue. Specify an HTML color value.

Type: string
Default: #00dd00
maxDepth

The maximum number of node levels to show in the current view. Levels will be flattened into the current plane. If your tree has more levels than this, you will have to go up or down to see them. You can additionally see maxPostDepth levels below this as shaded rectangles within these nodes.

Type: number
Default: 1
maxHighlightColor

The highlight color to use for the node with the largest value in column 3. Specify an HTML color value or null; If null, this value will be the value of maxColor lightened by 35%

Type: string
Default: null
maxPostDepth

How many levels of nodes beyond maxDepth to show in "hinted" fashion. Hinted nodes are shown as shaded rectangles within a node that is within the maxDepth limit.

Type: number
Default: 0
maxColorValue

The maximum value allowed in column 3. All values greater than this will be trimmed to this value. If set to null, it will be set to the max value in the column.

Type: number
Default: null
midColor

The color for a rectangle with a column 3 value midway between maxColorValue and minColorValue. Specify an HTML color value.

Type: string
Default: #000000
midHighlightColor

The highlight color to use for the node with a column 3 value near the median of minColorValue and maxColorValue. Specify an HTML color value or null; if null, this value will be the value of midColor lightened by 35%.

Type: string
Default: null
minColor

The color for a rectangle with the column 3 value of minColorValue. Specify an HTML color value.

Type: string
Default: #dd0000
minHighlightColor

The highlight color to use for the node with a column 3 value nearest to minColorValue. Specify an HTML color value or null; if null, this value will be the value of minColor lightened by 35%

Type: string
Default: null
minColorValue

The minimum value allowed in column 3. All values less than this will be trimmed to this value. If set to null, it will be calculated as the minimum value in the column.

Type: number
Default: null
noColor

The color to use for a rectangle when a node has no value for column 3, and that node is a leaf (or contains only leaves). Specify an HTML color value.

Type: string
Default: #000000
noHighlightColor

The color to use for a rectangle of "no" color when highlighted. Specify an HTML color value or null; if null, this will be the value of noColor lightened by 35%.

Type: string
Default: null
showScale

Whether or not to show a color gradient scale from minColor to maxColor along the top of the chart. Specify true to show the scale.

Type: boolean
Default: false
showTooltips

Whether to show tooltips.

Type: boolean
Default: true
textStyle

An object that specifies the text style, for certain charts that have text in the content area such as the treemap. The object has this format:

{ color: <string>,
  fontName: <string>,
  fontSize: <number>,
  bold: <boolean>,
  italic: <boolean> }
    

The color can be any HTML color string, for example: 'red' or '#00cc00'. Also see fontName and fontSize.

Type: object
Default: {color: 'black', fontName: <global-font-name>, fontSize: <global-font-size>}
title

Text to display above the chart.

Type: string
Default: no title
titleTextStyle

An object that specifies the title text style. The object has this format:

{ color: <string>,
  fontName: <string>,
  fontSize: <number>,
  bold: <boolean>,
  italic: <boolean> }
    

The color can be any HTML color string, for example: 'red' or '#00cc00'. Also see fontName and fontSize.

Type: object
Default: {color: 'black', fontName: <global-font-name>, fontSize: <global-font-size>}
useWeightedAverageForAggregation

Whether to use weighted averages for aggregation.

Type: boolean
Default: false

Methods

Method
draw(data, options)

Draws the chart.

Return Type: none
getSelection()

Standard getSelection() implementation. Selected elements are nodes. Only one node can be selected at a time.

Return Type: Array of selection elements
setSelection()

Standard setSelection() implementation. Selected elements are nodes. Only one node can be selected at a time.

Return Type: none
goUpAndDraw()

Move up the tree by one level and redraw it. Does not throw an error if the node is the root node. This is fired automatically when the user right-clicks a node.

Return Type: none
getMaxPossibleDepth()

Returns the maximum possible depth for the current view.

Return Type: number
clearChart()

Clears the chart, and releases all of its allocated resources.

Return Type: none

Events

Name
onmouseover

Fired when the user mouses over a node. The event handler is passed the row index of the corresponding entry in the data table.

Properties: row
onmouseout

Fired when the user mouses out of a node. The event handler is passed the row index of the corresponding entry in the data table.

Properties: row
ready

Fired when chart is ready for external method calls. If you want to interact with the chart, and call methods after you draw it, you should set up a listener for this event before you call the draw method, and call them only after the event was fired.

Properties: None
rollup

Fired when the user navigates back up the tree, typically by right-clicking. The row property passed into the event handler is the row of the node that the user is navigating from, not the row the user is navigating to.

Properties: row
select

Fired when the user clicks a node. To learn which node was selected, call getSelection().

Properties: none

Data Policy

All code and data are processed and rendered in the browser. No data is sent to any server.