Sankey diagram

Sankey visualisation

Updated 23 days ago to v4.0.0 by Flourish team

How to use this template

Sankey diagram

A template for creating Sankey diagrams and alluvial diagrams. Ideal for displaying energy flows or the changes in seats between parties from before to after an election.

Data requirements

The template works with two types of data format:

  1. Flows are already in the data, and each row has a source name, target name and flow value (plus optional step from and step to columns for multistep alluvial diagrams).

  2. Flows are not already in the data. In this model, each row is a entity (e.g. a seat in an election), with a source name and target name (e.g. representing the ruling party before and after the election). With this kind of data the flows are computed automatically by adding up source–target pairs (taking into account step from and step to values).

FAQ

How can I specify the ordering of the results? They're shown in a different order from my raw data In the settings panel, set "Iter" to 0.

Tips

  • If specifying flow values directly, the column used for Value of link must contain positive numbers or zero
  • Names are compared and values summed using case-insensitive comparisons with all non-alphanumeric characters stripped. For example “Cat“ and “cA ?t“ are considered identical.
  • Hovering over a link will defocus all other links and any node not connected to that link. Hovering over a node will defocus all links that are not directly connected to that node and all nodes not connected via a link to the hovered node. You can fix focus on a node or link and all its connections by clicking on the entity. This is particularly useful for guiding viewers through your stories. Click a focused node or link again to remove the focus or click any other node or link to change focus to that entity.
  • The optional Step from and Step to column selection boxes make it possible to construct multistep alluvial diagrams where links go from Step from to Step to along the horizontal direction. If only Step from is assigned to a column then the value of Step to is assumed to be one greater than that of Step from. Similarly, if only Step to is assigned to a column then the value of Step from is assumed to be one less than that of Step to.

This section documents API usage specific to this template, so for an introduction we suggest you refer to the generic API documentation instead.

template: @flourish/sankey

version: 4

Template data

There are two different formats in which you can supply data to this template. Which one will be more convenient for you likely depends on the source of your data, as described below.

Array of objects with arbitrary keys, and a bindings object

This format is most likely useful when you have data from an external source, such as CSV data loaded from d3-dsv. You should supply this attached to the opts.data, which might look like:

    {
        links: [
            { "LinksHeader1": ..., "LinksHeader2": ..., ... },
            { "LinksHeader1": ..., "LinksHeader2": ..., ... },
            { "LinksHeader1": ..., "LinksHeader2": ..., ... },
            ...
        ]
    }

... but with the keys being the column headers from your source data instead. To tell the API how these values from each column should be associated with the keys that the template is expecting, you must also supply an object attached to opts.bindings. (The meanings of the keys in the bindings object are documented below.) The minimal bindings you can supply for this template are as shown in this example:

{
    template: "@flourish/sankey",
    version: "4",
    bindings: {
        links: {
            source: "LinksHeader1",
            target: "LinksHeader2"
        }
    },
    data: {
        links: [
            { "LinksHeader1": ..., "LinksHeader2": ..., ... },
            { "LinksHeader1": ..., "LinksHeader2": ..., ... },
            { "LinksHeader1": ..., "LinksHeader2": ..., ... },
            ...
        ]
    }
}

All possible bindings that you can supply are shown in this example:

{
    template: "@flourish/sankey",
    version: "4",
    bindings: {
        links: {
            source: "LinksHeader1",
            target: "LinksHeader2",
            value: "LinksHeader3",
            step_from: "LinksHeader4",
            step_to: "LinksHeader5"
        }
    },
    data: {
        links: [
            { "LinksHeader1": ..., "LinksHeader2": ..., ... },
            { "LinksHeader1": ..., "LinksHeader2": ..., ... },
            { "LinksHeader1": ..., "LinksHeader2": ..., ... },
            ...
        ]
    }
}

(As before, the keys containing "Header" would be replaced by column names from your data source.)

Array of objects with template-defined keys

There is an alternative format you can use, which is likely to be easier to use if your data is not from a spreadsheet source. With this alternative format you supply your data to the template as an array of objects, attached to opts.data, where the keys must be those used by the template, as documented below. In this case there is no need to supply a bindings object, since the key names are already those expected by the template. The required properties in the data object are as follows (scroll down for a description of what each property is):

{
template: "@flourish/sankey",
version: "4",
data: {
    links: [
        {
            source: ...,
            target: ...
        },
        ...
    ]
},
...
}

And the full list of all possible properties is as follows:

{
template: "@flourish/sankey",
version: "4",
data: {
    links: [
        {
            source: ...,
            target: ...,
            value: ...,
            step_from: ...,
            step_to: ...
        },
        ...
    ]
},
...
}

Meanings of the template data keys:

  • links.source: source
  • links.target: target
  • links.value: A numerical value used to set the thickness of the links.
  • links.step_from: An integer value used to indicate where a link starts from (used only in Alluvial mode).
  • links.step_to: An integer value used to indicate where a link goes to (used only in Alluvial mode).

Template settings

Options for opts.state.

Format

mode string

Mode.

Allowed values:

  • alluvial (Alluvial (stepwise composition))
  • sankey (Sankey (arbitrary flows))

iterations number

Iter.. Number of iterations of the layout algorithm before the diagram is drawn. The higher the value, the fewer link crossings you will see but the less likely the order is to match that in the datasheet.

Max: 100

spread string

Spread.

Allowed values:

  • step (Based on step values)
  • column (Evenly)

alignment string

Alignment.

Allowed values:

  • justify (Justify)
  • center (Centre)
  • left (Left)
  • right (Right)

node_width number

Node width.

Min: 2

Max: 50

node_padding number

Vertical node margin.

Max: 20

top_padding number

Top margin. Adds space at the top of the diagram; useful to accommodate labels

Max: 50

bottom_padding number

Bottom margin. Adds space at the bottom of the diagram; useful to accommodate labels

Max: 50

color.scale_type string

Scale type.

Allowed values:

  • categorical (Categorical)
  • sequential (Sequential)
  • diverging (Diverging)

color.categorical_type string

Allowed values:

  • palette (Palette)
  • generated (Generated)

color.categorical_palette colors

Palette.

color.categorical_extend boolean

Auto-extend. Automatically generate additional colours when needed to avoid the palette colours being used more than once.

color.categorical_seed_color color

Seed color. Initial color in generated sequence (avoid shades of grey).

color.categorical_rotation_angle number

Hue rotation angle. Angle, in degrees, between one generated colour and the next. The default value, ~360/(Golden ratio), ensures adjacent hues are not too similar.

Max: 360

color.categorical_color_space string

Allowed values:

  • hcl (HCL)
  • hsl (HSL)

color.categorical_custom_palette text

Custom overrides. Type the name of the entity whose colour you want to set, a colon and then a colour (using a name, hex-code or rgb declaration). Multiple colours can be set using multiple lines. For example:<br /><hr />Party 1: red<br />Party 2: #4455AA<br />Party 3: rgb(30,168,26)

color.sequential_palette string

Palette.

Allowed values:

  • Oranges
  • Reds
  • Blues
  • Greens
  • Greys
  • Purples
  • Viridis
  • Inferno
  • Magma
  • Plasma
  • Warm
  • Cool
  • CubehelixDefault (Cubehelix)
  • BuGn (Blue/Green)
  • BuPu (Blue/Purple)
  • GnBu (Green/Blue)
  • OrRd (Orange/Red)
  • PuBuGn (Purple/Blue/Green)
  • PuBu (Purple/Blue)
  • PuRd (Purple/Red)
  • RdPu (Red/Purple)
  • YlGnBu (Yellow/Blue/Green)
  • YlGn (Yellow/Green)
  • YlOrBr (Yellow/Orange/Brown)
  • YlOrRd (Yellow/Orange/Red)
  • Carrots
  • Custom

color.sequential_custom_min color

Minimum color.

color.sequential_custom_max color

Maximum color.

color.sequential_color_space string

Allowed values:

  • rgb (RGB)
  • lab (LAB)
  • hcl (HCL)
  • hsl (HSL)

color.sequential_reverse boolean

Reverse scale.

color.diverging_palette string

Palette.

Allowed values:

  • RdBu (Red/Blue)
  • RdYlGn (Red/Yellow/Green)
  • PiYG (Pink/Yellow/Green)
  • BrBG (Brown/Blue/Green)
  • PRGn (Purple/Red/Green)
  • PuOr (Purple/Orange)
  • RdGy (Red/Grey)
  • RdYlBu (Red/Yellow/Blue)
  • Spectral
  • Custom

color.diverging_custom_min color

Minimum color.

color.diverging_custom_mid color

Midpoint color.

color.diverging_custom_max color

Maximum color.

color.diverging_color_space string

Allowed values:

  • rgb (RGB)
  • lab (LAB)
  • hcl (HCL)
  • hsl (HSL)

color.diverging_reverse boolean

Reverse scale.

Link opacity.

Max: 1

background_opacity number

Defocused opacity. When a node or link is in focus, this sets the opacity of the others

Max: 1

Labels

label_mode string

Allowed values:

  • outwards (Favour outside)
  • inwards (Favour inside)

label_color_mode string

Text.

Allowed values:

  • none (None)
  • auto (Auto)
  • fixed (Fixed)

label_color color

 .

label_outline_color_mode string

Outline.

Allowed values:

  • none (None)
  • auto (Auto)
  • fixed (Fixed)

label_outline_color color

 .

label_responsive boolean

Sizing. Auto changed the label size based on the window size, subject to the specified min and max

Allowed values:

  • true (Auto)
  • false (Fixed)

label_font_size number

In pixels.

label_font_size_min number

Min.

label_font_size_max number

Max.

label_bold boolean

Bold.

label_show_values boolean

Show node values.

Allowed values:

  • true (None)
  • false (All)

Show link values.

Allowed values:

  • never (None)
  • focused (Focused)
  • always (All)

Colour.

Number formatting

localization.input_decimal_separator string

Decimal separator in data sheet. Used for interpreting your data. Only change if data is not displaying on the chart as expected.

Allowed values:

  • . (.)
  • , (,)

localization.output_separators string

Number format to display. How the numbers should appear on chart labels

Allowed values:

  • ,. (12,235.67)
  • ., (12.345,67)
  • . (12235.67)
  • , (12345,67)
  • . (12 235.67)
  • , (12 345,67)

formatting.prefix string

Prefix. Text to place in front of number

formatting.suffix string

Suffix. Text to place after number

formatting.n_dec number

Decimal places. Use negative integers to round to positive powers of ten (eg -2 rounds to the nearest 100)

Min: -10

Max: 10

formatting.strip_zeros boolean

Remove trailing zeros.

formatting.strip_separator boolean

Hide thousands separator below 10,000. Turn off if you want four-digit numbers to include a separator, e.g. “1,234” rather than “1234”.

formatting.transform_labels boolean

Multiply/divide values.

formatting.transform string

Allowed values:

  • multiply (Multiply by)
  • divide (Divide by)
  • exponentiate (×10 to the power of)

formatting.multiply_divide_constant number

formatting.exponentiate_constant number

Layout

layout.body_font font

Font.

layout.max_width number

Maximum width. Leave blank to stretch to container width

Min: 50

layout.margin number

Margin.

layout.background_color_enabled boolean

Color.

Allowed values:

  • true (On)
  • false (Off)

layout.background_image_enabled boolean

Image.

Allowed values:

  • true (On)
  • false (Off)

layout.background_color color

Color.

layout.background_image_src url

Image URL.

layout.background_image_size string

Size.

Allowed values:

  • cover (Fill)
  • contain (Fit)
  • auto (Original)
  • 100% 100% (Stretch)

layout.background_image_position string

Position.

Allowed values:

  • top left (Top left)
  • top center (Top center)
  • top right (Top right)
  • center left (Center left)
  • center center (Center)
  • center right (Center right)
  • bottom left (Bottom left)
  • bottom center (Bottom center)
  • bottom right (Bottom right)

layout.layout_order string

Layout order.

Allowed values:

  • stack-default (data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABYAAAAdCAYAAAHZdKxuAAAAAXNSR0IArs4c6QAAANhJREFUSA3tVNEOwiAM7Iy/p2/wkTz6g5gjOVZZEepcjMmWLBTau95ugIh6lpzzLcb4wNpFJaRk9MIahxAyXmD7mC7BC2RlFbliQjFMpJTujOdGs/ECwRoP3rlKoEzNJlz3+CwutK0NLRVt2QhjggA9n2IGEKANMxmt0VVsEfxgzfX7zL3ZiqbXLjcKc8vEORk5/75mMB/7u11uuIpdbtDCc5R3l/s+e+pmHt1foza7Nv6IXOeHiqGk9zWtSk1cN2cPrItnYjZzHZEZYtacxHTiuANSO/xN8AS4uW8Rw1Gu2AAAAABJRU5ErkJggg==)
  • stack-2 (data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABYAAAAdCAYAAAHZdKxuAAAAAXNSR0IArs4c6QAAAMpJREFUSA3tVMsKwyAQNKW/l970Iz32Bw0jjKTrSLUY0oOBsO5rnOwYnTs9W0ppDyG8EcsOkw8uauu9T3jR2+75yJxBnnC4JxMxxlezg0V9VsJsIGz75TfKdlkpg3aPcT8TsPNRMJjZEIf5xaAAahUyE+RtfcZvtFLoFh95aFXxH4hCWpUoTCg7fxqUfB4yEcl/CJlNy5qbfuZA8m8CwJ77q2djSj50lnuAWbOAOQlXxCuRHxcUje2XzfgrYzBpHUXLkmxh181SpnEAB4Vg0DSGhHsAAAAASUVORK5CYII=)

layout.space_between_sections string

Space between sections.

Allowed values:

  • 0 (▁)
  • 0.5 (▃)
  • 1 (▄)
  • custom (...)

layout.space_between_sections_custom number

Custom.

Max: 100

layout.header_align string

Alignment.

Allowed values:

  • left (fa-align-left)
  • center (fa-align-center)
  • right (fa-align-right)

layout.title string

layout.title_styling boolean

Change title styles.

layout.title_size string

Size.

Allowed values:

  • 1.4 (ᴀ)
  • 1.6 (A)
  • 2 (fa-font)
  • custom (...)

layout.title_size_custom number

Custom. Specify a custom responsive font size. Best results will be with values between 1.2 and 3

layout.title_weight string

Weight.

Allowed values:

  • bold (Bold)
  • normal (Regular)

layout.title_color color

Color.

layout.title_line_height number

Line height.

Max: 3

layout.subtitle string

layout.subtitle_styling boolean

Change subtitle styles.

layout.subtitle_size string

Size.

Allowed values:

  • 1.4 (ᴀ)
  • 1.6 (A)
  • 2 (fa-font)
  • custom (...)

layout.subtitle_size_custom number

Custom. Specify a custom responsive font size. Best results will be with values between 1.2 and 3

layout.subtitle_weight string

Weight.

Allowed values:

  • bold (Bold)
  • normal (Regular)

layout.subtitle_color color

Color.

layout.subtitle_line_height number

Line height.

Max: 3

layout.subtitle_space_above string

Space above.

Allowed values:

  • 0 (▁)
  • 0.5 (▃)
  • 1 (▄)
  • custom (...)

layout.subtitle_space_above_custom number

Custom.

Max: 100

layout.text string

layout.text_styling boolean

Change text styles.

layout.text_size string

Size.

Allowed values:

  • 1.2 (ᴀ)
  • 1.4 (A)
  • 1.6 (fa-font)
  • custom (...)

layout.text_size_custom number

Custom. Specify a custom responsive font size. Best results will be with values between 1.2 and 3

layout.text_weight string

Weight.

Allowed values:

  • bold (Bold)
  • normal (Regular)

layout.text_color color

Color.

layout.text_line_height number

Line height.

Max: 3

layout.text_space_above string

Space above.

Allowed values:

  • 0 (▁)
  • 0.5 (▃)
  • 1 (▄)
  • custom (...)

layout.text_space_above_custom number

Custom.

Max: 100

layout.source_name string

Source name.

layout.source_url string

Source url.

layout.multiple_sources boolean

Multiple sources.

layout.source_name_2 string

Source name.

layout.source_url_2 string

Source url.

layout.source_name_3 string

Source name.

layout.source_url_3 string

Source url.

layout.source_label string

Source label.

layout.note string

Note.

layout.size number

Size.

layout.color color

Color.

layout.footer_align string

Alignment.

Allowed values:

  • left (fa-align-left)
  • center (fa-align-center)
  • right (fa-align-right)
  • justify (fa-align-justify)

layout.logo_url url

Image.

Link.

layout.logo_height number

Height.

layout.logo_margin number

Margin.

layout.logo_order string

Position.

Allowed values:

  • left (Left)
  • right (Right)

layout.footer_align_vertical string

V. align.

Allowed values:

  • flex-start (Top)
  • center (Center)
  • flex-end (Bottom)