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Angular Charts: Treemap Series

Treemap series is used to render hierarchical data structures or trees, where each node in the tree is represented by a rectangle, and the value of a node by the area of its rectangle.

The bigger the value, the bigger the rectangle is relative to its siblings. Parent nodes are represented by rectangles with areas that are the totals of their children.

If the nodes have no value, then their area is divided equally among siblings within their parent node.

The Ag Charts treemap series uses a popular "squarified" tiling algorithm which tries to keep each node's rectangle as square as possible.

Treemap series would be a great fit for visualizing a directory structure (the original purpose of the algorithm), components of a stock market index, shares of products within product categories, or sales breakdown by city, state, and country. And these are just a few examples.

Basic Configuration

cartesian and polar charts are used with linear data or, in other words, arrays. Since treemaps are used to render tree data, to create a basic treemap, we need to use a hierarchy chart.

A basic treemap configuration would look like this:

type: 'hierarchy',
data, // the root node of the hierarchy
series: [{
    type: 'treemap',
    labelKey: 'label', // the name of the key to fetch the label value from
    sizeKey: 'size',   // the name of the key to fetch the value that will determine tile size
    colorKey: 'color', // the name of the key to fetch the value that will determine tile color
}]

The data should be a tree structure, where parent nodes use the children property to list their children:

let data = {
    label: 'Root',
    children: [
        {
            label: 'Utilities',
            children: [{
                label: 'AWK',
                size: 252
            }]
        },
        ...
    ]
}

Notice, that only the leaf nodes of a tree are required to have the sizeKey property. The size of the parent nodes will be automatically determined.

The labelKey, sizeKey and colorKey configs can be omitted, if the node objects in your data happen to have the label, size and color fields.

Any treemap series covers the whole series area of a chart, so it doesn't make sense to have more than a single treemap series in a chart, even though it's technically supported.

Let's take a look at how we can use the treemap series to render a snapshot of the S&P 500 stock market index. Feel free to open this example in Plunker to enlarge the size of the component and notice how the treemap reveals more data as it grows bigger.

Stock Market Index Example

Alternative Configuration

Although not very common, treemaps can be used to show the hierarchy without emphasizing size. In such a case, you can set the sizeKey to undefined. This will make all sibling tiles within the same parent have the same area (but not necessarily the same shape).

The org chart example below takes advantage of that by using the following config:

series: [{
    type: 'treemap',
    labelKey: 'orgHierarchy',
    sizeKey: undefined,  // make all siblings within a parent the same size
    colorKey: undefined, // use node depth value to determine the tile color
    groupFill: 'black',  // the color of group tiles, retrieved from data if `undefined`
    colorDomain: [0, 2, 4], // depth of 0 will correspond to 'red', 2 to 'green' and so on
    colorRange: ['red', 'green', 'blue'], // tiles with a depth of 1 will be a blend of 'red' and 'green'
    // change the color of a particular tile
    formatter: ({ datum, labelKey, highlighted }) => {
        if (datum[labelKey] === 'Joel Cooper') {
            return { fill: highlighted ? 'white' : 'orchid' };
        }
    },
}]

Organizational Chart Example

Understanding the Treemap colours

There are several ways to customise the colours of treemap tiles.

Storing the colour values in the data

If treemap data nodes have fill colours assigned to them, the property containing the colour should be specified in colorKey.

series: [{
    type: 'treemap',
    colorKey: 'color',
    data: [{
        children: [
            { color: 'red' },
            { color: '#fa5310' },
        ],
    }],
}]

Using the color scale

colorKey can also specify a property containing a numeric value. In this case the colorDomain and colorRange should be provided.

series: [{
    type: 'treemap',
    colorKey: 'color',
    colorDomain: [0, 10, 20],
    colorRange: ['red', 'yellow', 'green'],
    data: [{
        children: [
            { color: 5 },
            { color: 8 },
            { color: 12 },
        ],
    }],
}]

Groups colours

The groups can be coloured in 2 ways:

  • A static colour value can be specified in groupFill property.
  • If groupFill can be set to undefined, the group colour behaviour will match the one for tiles.
series: [{
    type: 'treemap',
    colorKey: 'color',
    groupFill: 'black',
    ...
    groupFill: undefined,
    data: [{
        color: 'black',
        children: [
            { color: 'white' },
            { color: 'red' },
            { color: 'white' },
        ],
    }],
}]

Strokes

There are several properties to control the tiles' and groups' stroke colors and widths.

series: [{
    type: 'treemap',
    tileStroke: 'black',
    tileStrokeWidth: 2,
    groupStroke: 'transparent',
    groupStrokeWidth: 0,
}]

Labels colours and font styles

Since tiles can have different sizes depending on layout, there is large, medium and small label configuration to match a specific size. Tiles can also have separate value labels. The styles for all of them can be specified like:

series: [{
    type: 'treemap',
    labels: {
        large: {
            color: 'black',
            fontWeight: 'bold',
        },
        medium: {
            color: 'black',
        },
        small: {
            color: 'gray',
            fontSize: 8,
        },
        value: {
            formatter: ({ datum }) => `${datum.size * 100}%`,
            style: {
                color: 'orange',
            },
        },
    },
}]

In addition the groups' titles can have their own styles:

series: [{
    type: 'treemap',
    title: {
        color: 'black',
        fontWeight: 'bold',
    },
    subtitle: {
        color: 'black',
        fontSize: 8,
    },
}]

Overriding the styles for particular tiles

Use formatter function to change a colour for specific tiles.

series: [{
    formatter: ({ datum, depth, labelKey, highlighted }) => {
        if (datum[labelKey] === 'Joel Cooper') {
            return { fill: highlighted ? 'white' : 'orchid' };
        }
    },
}]

Please see the API reference for more information.

Complex Colouring Chart Example

API Reference

Properties available on the AgTreemapSeriesOptions<DatumType = any> interface.

type
'treemap'
'treemap'
title
AgTreemapSeriesLabelOptions
The label configuration for the top-level tiles.
title: AgTreemapSeriesLabelOptions;

interface AgTreemapSeriesLabelOptions {
  // The amount of the tile's vertical space to reserve for the label. 
  padding?: number;
  // Whether or not the labels should be shown. 
  enabled?: boolean;
  // The font style to use for the labels. 
  fontStyle?: FontStyle;
  // The font weight to use for the labels. 
  fontWeight?: FontWeight;
  // The font size in pixels to use for the labels. 
  fontSize?: FontSize;
  // The font family to use for the labels. 
  fontFamily?: FontFamily;
  // The colour to use for the labels. 
  color?: CssColor;
}

type FontStyle = 
      'normal' 
    | 'italic' 
    | 'oblique'


type FontWeight = 
      'normal' 
    | 'bold' 
    | 'bolder' 
    | 'lighter' 
    | '100' 
    | '200' 
    | '300' 
    | '400' 
    | '500' 
    | '600' 
    | '700' 
    | '800' 
    | '900'


type FontSize = number

type FontFamily = string

type CssColor = string
subtitle
AgTreemapSeriesLabelOptions
The label configuration for the children of the top-level parent tiles.
subtitle: AgTreemapSeriesLabelOptions;

interface AgTreemapSeriesLabelOptions {
  // The amount of the tile's vertical space to reserve for the label. 
  padding?: number;
  // Whether or not the labels should be shown. 
  enabled?: boolean;
  // The font style to use for the labels. 
  fontStyle?: FontStyle;
  // The font weight to use for the labels. 
  fontWeight?: FontWeight;
  // The font size in pixels to use for the labels. 
  fontSize?: FontSize;
  // The font family to use for the labels. 
  fontFamily?: FontFamily;
  // The colour to use for the labels. 
  color?: CssColor;
}

type FontStyle = 
      'normal' 
    | 'italic' 
    | 'oblique'


type FontWeight = 
      'normal' 
    | 'bold' 
    | 'bolder' 
    | 'lighter' 
    | '100' 
    | '200' 
    | '300' 
    | '400' 
    | '500' 
    | '600' 
    | '700' 
    | '800' 
    | '900'


type FontSize = number

type FontFamily = string

type CssColor = string
labels
AgTreemapSeriesLabelsOptions
Configuration for the tile labels.
labels: AgTreemapSeriesLabelsOptions;

interface AgTreemapSeriesLabelsOptions {
  // The label configuration for the large leaf tiles. 
  large?: AgChartLabelOptions;
  // The label configuration for the medium-sized leaf tiles. 
  medium?: AgChartLabelOptions;
  // The label configuration for the small leaf tiles. 
  small?: AgChartLabelOptions;
  // The configuration for the cell value label. 
  value?: { key?: string; name?: string; formatter?: (params: { datum: any; }) => string | undefined; style?: AgChartLabelOptions; };
}

interface AgChartLabelOptions {
  // Whether or not the labels should be shown. 
  enabled?: boolean;
  // The font style to use for the labels. 
  fontStyle?: FontStyle;
  // The font weight to use for the labels. 
  fontWeight?: FontWeight;
  // The font size in pixels to use for the labels. 
  fontSize?: FontSize;
  // The font family to use for the labels. 
  fontFamily?: FontFamily;
  // The colour to use for the labels. 
  color?: CssColor;
}

type FontStyle = 
      'normal' 
    | 'italic' 
    | 'oblique'


type FontWeight = 
      'normal' 
    | 'bold' 
    | 'bolder' 
    | 'lighter' 
    | '100' 
    | '200' 
    | '300' 
    | '400' 
    | '500' 
    | '600' 
    | '700' 
    | '800' 
    | '900'


type FontSize = number

type FontFamily = string

type CssColor = string
labelKey
string
The name of the node key containing the label.
Default: 'label'
sizeKey
string
The name of the node key containing the size value.
Default: 'size'
colorKey
string
The name of the node key containing the color value. This value (along with colorDomain and colorRange configs) will be used to determine the tile color.
Default: 'color'
colorDomain
number[]
The domain the 'colorKey' values belong to. The domain can contain more than two stops, for example [-5, 0, -5]. In that case the 'colorRange' should also use a matching number of colors.
Default: [-5, 5]
colorRange
string[]
The color range to interpolate the numeric colorDomain into. For example, if the colorDomain is [-5, 5] and colorRange is ['red', 'green'], a colorKey value of -5 will be assigned the 'red' color, 5 - 'green' color and 0 a blend of 'red' and 'green'.
Default: ['#cb4b3f', '#6acb64']
groupFill
string
The group fill color. If undefined the value based on colorKey will be used.
Default: '#272931'
groupStroke
string
The group's stroke color.
groupStrokeWidth
number
The group's stroke width.
tileStroke
string
The tile's stroke color.
tileStrokeWidth
number
The tile's stroke width.
tooltip
AgTreemapSeriesTooltip<DatumType>
Series-specific tooltip configuration.
tooltip: AgTreemapSeriesTooltip<DatumType>;

interface AgTreemapSeriesTooltip<DatumType> {
  // Function used to create the content for tooltips. 
  renderer?: (params: AgTreemapSeriesTooltipRendererParams<DatumType>) => string | AgTooltipRendererResult;
  // Whether or not to show tooltips when the series are hovered over. 
  enabled?: boolean;
}

interface AgTreemapSeriesTooltipRendererParams<DatumType> {
  // Datum from the series data that the treemap tile is being rendered for. 
  datum: DatumType;
  // The parent of the datum from the treemap data. 
  parent?: DataValue;
  // The depth of the datum in the hierarchy. 
  depth: number;
  // sizeKey as specified on series options. 
  sizeKey?: string;
  // labelKey as specified on series options. 
  labelKey?: string;
  // colorKey as specified on series options. 
  colorKey?: string;
  // The computed fill colour of the treemap tile. 
  color?: string;
  // The title of the treemap tile 
  title?: string;
  // The ID of the series. 
  seriesId: string;
}

type DataValue = any

interface AgTooltipRendererResult {
  // Title text for the tooltip header. 
  title?: string;
  // Content text for the tooltip body. 
  content?: string;
  // Tooltip title text color. 
  color?: string;
  // Tooltip title background color. 
  backgroundColor?: string;
}
nodePadding
PixelSize
The amount of padding in pixels inside of each treemap tile. Increasing nodePadding will reserve more space for parent labels.
nodePadding: PixelSize;

type PixelSize = number
gradient
boolean
Whether or not to use gradients for treemap tiles.
Default: true
tileShadow
AgDropShadowOptions
Configuration for the shadow used behind the treemap tiles.
tileShadow: AgDropShadowOptions;

interface AgDropShadowOptions {
  // Whether or not the shadow is visible. 
  enabled?: boolean;
  // The colour of the shadow. 
  color?: CssColor;
  // The horizontal offset in pixels for the shadow. 
  xOffset?: PixelSize;
  // The vertical offset in pixels for the shadow. 
  yOffset?: PixelSize;
  // The radius of the shadow's blur, given in pixels. 
  blur?: PixelSize;
}

type CssColor = string

type PixelSize = number
labelShadow
AgDropShadowOptions
Configuration for the shadow used behind the treemap labels.
labelShadow: AgDropShadowOptions;

interface AgDropShadowOptions {
  // Whether or not the shadow is visible. 
  enabled?: boolean;
  // The colour of the shadow. 
  color?: CssColor;
  // The horizontal offset in pixels for the shadow. 
  xOffset?: PixelSize;
  // The vertical offset in pixels for the shadow. 
  yOffset?: PixelSize;
  // The radius of the shadow's blur, given in pixels. 
  blur?: PixelSize;
}

type CssColor = string

type PixelSize = number
highlightGroups
boolean
Determines whether the groups will be highlighted by cursor.
highlightStyle
AgTreemapSeriesHighlightStyle
Configuration for treemap tiles when they are hovered over.
highlightStyle: AgTreemapSeriesHighlightStyle;

interface AgTreemapSeriesHighlightStyle {
  // Highlight style used for a text when item is tapped or hovered over. 
  text?: AgTreemapSeriesHighlightTextStyle;
  // Highlight style used for an individual marker when tapped or hovered over. 
  item?: AgSeriesHighlightMarkerStyle;
  // Highlight style used for whole series when one of its markers is tapped or hovered over. 
  series?: AgSeriesHighlightSeriesStyle;
}

interface AgTreemapSeriesHighlightTextStyle {
  // The colour of an item's text when tapped or hovered over. Use `undefined` for no highlight. 
  color?: CssColor;
}

type CssColor = string

interface AgSeriesHighlightMarkerStyle {
  // The fill colour of a marker when tapped or hovered over. Use `undefined` for no highlight. 
  fill?: CssColor;
  // The opacity of the fill for the highlighted item. 
  fillOpacity?: Opacity;
  // The stroke colour of a marker when tapped or hovered over. Use `undefined` for no highlight. 
  stroke?: CssColor;
  // The stroke width of a marker when tapped or hovered over. Use `undefined` for no highlight. 
  strokeWidth?: PixelSize;
}

type Opacity = number

type PixelSize = number

interface AgSeriesHighlightSeriesStyle {
  enabled?: boolean;
  // The opacity of the whole series (area line, area fill, labels and markers, if any) when another chart series or another stack level in the same area series is highlighted by hovering a data point or a legend item. Use `undefined` or `1` for no dimming. 
  dimOpacity?: Opacity;
  // The stroke width of the area line when one of the markers is tapped or hovered over, or when a tooltip is shown for a data point, even when series markers are disabled. Use `undefined` for no highlight. 
  strokeWidth?: PixelSize;
}
formatter
Function
A callback function for adjusting the styles of a particular treemap tile based on the input parameters
formatter = (
    params: AgTreemapSeriesFormatterParams<DataValue>
) => AgTreemapSeriesFormat;

interface AgTreemapSeriesFormatterParams<DataValue = any> {
  // Datum from the series data that the treemap tile is being rendered for. 
  datum: DataValue;
  // The parent of the datum from the treemap data. 
  parent?: DataValue;
  // The depth of the datum in the hierarchy. 
  depth: number;
  // labelKey as specified on series options. 
  labelKey: string;
  // sizeKey as specified on series options. 
  sizeKey?: string;
  // colorKey as specified on series options. 
  colorKey?: string;
  // The colour of the fill for the treemap tile. 
  fill?: CssColor;
  // The opacity of the fill for the treemap tile. 
  fillOpacity?: Opacity;
  // The colour of the stroke for the treemap tile. 
  stroke?: CssColor;
  // The opacity of the stroke for the treemap tile. 
  strokeOpacity?: Opacity;
  // The width in pixels of the stroke for the treemap tile. 
  strokeWidth?: PixelSize;
  // Whether or not the gradients are used for treemap tiles. 
  gradient?: boolean;
  // `true` if the tile is highlighted by hovering 
  highlighted: boolean;
  // The ID of the series. 
  seriesId: string;
}

type DataValue = any

type CssColor = string

type Opacity = number

type PixelSize = number

interface AgTreemapSeriesFormat {
  // The colour of the fill for the treemap tile. 
  fill?: CssColor;
  // The opacity of the fill for the treemap tile. 
  fillOpacity?: Opacity;
  // The colour of the stroke for the treemap tile. 
  stroke?: CssColor;
  // The opacity of the stroke for the treemap tile. 
  strokeOpacity?: Opacity;
  // The width in pixels of the stroke for the treemap tile. 
  strokeWidth?: PixelSize;
  // Whether or not the gradient is used for the treemap tile. 
  gradient?: boolean;
}
listeners
AgSeriesListeners<DatumType>
A map of event names to event listeners.
listeners: AgSeriesListeners<DatumType>;

interface AgSeriesListeners<DatumType> {
  // The listener to call when a node (marker, column, bar, tile or a pie sector) in the series is clicked. 
  nodeClick: (params: AgSeriesNodeClickParams<DatumType>) => void;
}

interface AgSeriesNodeClickParams<DatumType> {
  // Event type. 
  type: 'nodeClick';
  // Series ID, as specified in series.id (or generated if not specified) 
  seriesId: string;
  // Datum from the series data array. 
  datum: DatumType;
  // xKey as specified on series options 
  xKey?: string;
  // yKey as specified on series options 
  yKey?: string;
  // sizeKey as specified on series options 
  sizeKey?: string;
  // labelKey as specified on series options 
  labelKey?: string;
  // colorKey as specified on series options 
  colorKey?: string;
  // angleKey as specified on series options 
  angleKey?: string;
  // calloutLabelKey as specified on series options 
  calloutLabelKey?: string;
  // sectorLabelKey as specified on series options 
  sectorLabelKey?: string;
  // radiusKey as specified on series options 
  radiusKey?: string;
}
id
string
Primary identifier for the series. This is provided as seriesId in user callbacks to differentiate multiple series. Auto-generated ids are subject to future change without warning, if your callbacks need to vary behaviour by series please supply your own unique id value.
Default: auto-generated value
data
DatumType[]
The data to use when rendering the series. If this is not supplied, data must be set on the chart instead.
visible
boolean
Whether or not to display the series.
showInLegend
boolean
Whether or not to include the series in the legend.
cursor
string
The cursor to use for hovered area markers. This config is identical to the CSS cursor property.

Next Up

Continue to the next section to learn about combination charts.