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:
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).
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.
API information
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: 9
Template data
There are three different formats in which you can supply data to this template. The most convenient for you to use likely depends on the source of your data, as described below.
1. Array of arrays, and a bindings object
You can supply arrays of arrays to opts.data, which might look
like:
{
data: {
data: [
[ "DataColumn1Value1", "DataColumn2Value1",
[ "DataColumn1Value2", "DataColumn2Value2",
[ "DataColumn1Value3", "DataColumn2Value3",
...
]
}
}
where each array of arrays represents the rows in a data sheet.
To tell the API how the 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: "9",
bindings: {
data: {
source: 0, // index of a column in your data
target: 1, // index of a column in your data
}
},
data: {
data: [
[ "DataColumn1Value1", "DataColumn2Value1",
[ "DataColumn1Value2", "DataColumn2Value2",
[ "DataColumn1Value3", "DataColumn2Value3",
...
]
}
}
All possible bindings that you can supply are shown in this example:
{
template: "@flourish/sankey",
version: "9",
bindings: {
data: {
source: 0, // index of a column in your data
target: 1, // index of a column in your data
value: 2, // index of a column in your data
filter: 3, // index of a column in your data
facet: 4, // index of a column in your data
step_from: 5, // index of a column in your data
step_to: 6, // index of a column in your data
}
},
data: {
data: [
[ "DataColumn1Value1", "DataColumn2Value1",
[ "DataColumn1Value2", "DataColumn2Value2",
[ "DataColumn1Value3", "DataColumn2Value3",
...
]
}
}
2. 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:
{
data: [
{ "DataHeader1": ..., "DataHeader2": ..., ... },
{ "DataHeader1": ..., "DataHeader2": ..., ... },
{ "DataHeader1": ..., "DataHeader2": ..., ... },
...
]
}
... but with the keys being the column headers from your
source data instead. You must also supply an object attached to
opts.bindings. The minimal bindings you can
supply for this template are as shown in this example:
{
template: "@flourish/sankey",
version: "9",
bindings: {
data: {
source: "DataHeader1",
target: "DataHeader2",
}
},
data: {
data: [
{ "DataHeader1": ..., "DataHeader2": ..., ... },
{ "DataHeader1": ..., "DataHeader2": ..., ... },
{ "DataHeader1": ..., "DataHeader2": ..., ... },
...
]
}
}
All possible bindings that you can supply are shown in this example:
{
template: "@flourish/sankey",
version: "9",
bindings: {
data: {
source: "DataHeader1",
target: "DataHeader2",
value: "DataHeader3",
filter: "DataHeader4",
facet: "DataHeader5",
step_from: "DataHeader6",
step_to: "DataHeader7",
}
},
data: {
data: [
{ "DataHeader1": ..., "DataHeader2": ..., ... },
{ "DataHeader1": ..., "DataHeader2": ..., ... },
{ "DataHeader1": ..., "DataHeader2": ..., ... },
...
]
}
}
(As before, the keys containing "Header" would be replaced by column names from your data source.)
3. 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: "9",
data: {
data: [
{
source: ...,
target: ...
},
...
]
},
...
}
And the full list of all possible properties is as follows:
{
template: "@flourish/sankey",
version: "9",
data: {
data: [
{
source: ...,
target: ...,
value: ...,
filter: ...,
facet: ...,
step_from: ...,
step_to: ...
},
...
]
},
...
}
Meanings of the template data keys:
- data.source: source string
- data.target: target string
- data.value: A numerical value used to set the thickness of the links. number
- data.filter: filter string, number, datetime
- data.facet: facet string
- data.step_from: An integer value used to indicate where a link starts from (used only in Alluvial mode). number
- data.step_to: An integer value used to indicate where a link goes to (used only in Alluvial mode). number
Template metadata
Note: metadata is optional, and the API will interpret your data for you if you do not specify it. A typical example of when specifying metadata can be useful is when column(s) in your data contain numbers or dates that you wish to format visually (e.g. to display a column containing MM/DD/YYYY dates in DD/MM/YYYY format).
This template supports an optional metadata property. metadata informs the template what type of data is in each of your columns, and how that data should be formatted visually.
You can specify metadata in one of three formats, depending on the format of opts.data.
1. Array of objects with column indexes as keys
You should supply metadata in this format when opts.data is in the previously described 'array of arrays' format. In this case, metadata should be an object with column index: column type object key/value pairs (column type objects must have type, type_id, and output_format_id keys, documented below):
{
template: "@flourish/sankey",
version: "9",
...
data: {
data: [
[ "DataColumn1Value1", "DataColumn2Value1",
[ "DataColumn1Value2", "DataColumn2Value2",
[ "DataColumn1Value3", "DataColumn2Value3",
...
]
},
metadata: {
data: {
0: { type: ..., type_id: ..., output_format_id: ... },
1: { type: ..., type_id: ..., output_format_id: ... },
}
},
...
}
2. Array of objects with column headers as keys
You should supply metadata in this format when opts.data is in the previously described 'array of objects with arbitrary keys' format. In this case, metadata should be an object with column header: column type object key/value pairs (column type objects must have type, type_id, and output_format_id keys, documented below):
{
template: "@flourish/sankey",
version: "9",
data: {
data: [
{ "DataHeader1": ..., "DataHeader2": ..., ... },
{ "DataHeader1": ..., "DataHeader2": ..., ... },
{ "DataHeader1": ..., "DataHeader2": ..., ... },
...
]
},
metadata: {
data: {
"DataHeader1": { type: ..., type_id: ..., output_format_id: ... },
"DataHeader2": { type: ..., type_id: ..., output_format_id: ... },
}
},
...
}
Column type objects:
Column type objects tell the API what type of data is in a column:
{
type: "number", // options also include 'string', and 'datetime'
type_id: "number$comma_point", // numbers in the format 13,429.17
output_format_id: "number$space_comma", // numbers in the format 13 429,17
}
For more information on valid column type values, see Recognized Type Formats.
Template settings
Options for opts.state.
Mode & setup
mode string
Mode. Allowed values:
spread string
Spread. Allowed values:
alignment string
Alignment. Allowed values:
iterate boolean
Sorting. Allowed values:
iterations number
Iterations. 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. Min: 1 Max: 100
setup_settings boolean
Advanced.
node_width number
Node width. Min: 2 Max: 50
node_padding number
Node spacing. The vertical gap between nodes Max: 20
top_padding number
Margin above. Adds space at the top of the diagram; useful to accommodate any overflowing labels Max: 50
bottom_padding number
Margin below. Adds space at the bottom of the diagram; useful to accommodate any overflowing labels Max: 50
height_mode string
Height mode. Whether responsive embeds should set their own height or use the "standard" responsive Flourish embed heights. Ignored in simple iframe embeds, Canva and other fixed-height contexts. Allowed values:
facet_aspect number
Aspect. Aspect ratio of each plot in desktop mode, where 1 is square, above 1 is wider, and below 1 is taller. Min: 0.01
Grid of charts
facets.columns_fixed boolean
Number of columns. In Auto mode, the number of columns will change with screen size Allowed values:
facets.min_width number
Min chart width. Determines how many columns of charts there should be in the grid. Ignored if you specify a fixed number of columns.
facets.max_width number
Max chart width. Determines how many columns of charts there should be in the grid. Ignored if you specify a fixed number of columns.
facets.columns number
Fixed number of columns. Min: 1
facets.gutter_w number
Horizontal margin.
facets.gutter_h number
Vertical margin.
facets.animation string
On data change. If a chart in the grid is removed, that cell can either be animated out (with another cell moving to take its place) or reused for the new data in that cell. Auto decides for you based on the data. Allowed values:
facets.titles boolean
Show titles.
facets.title_align string
Alignment. Allowed values:
facets.title_size number
Size. Relative to the width of the chart
facets.title_unit string
Scale with chart. Allowed values:
facets.title_color color
Color.
facets.title_padding_top number
Space above.
facets.title_padding_bottom number
Space below.
facets.title_bg string
Background. Allowed values:
facets.title_bg_color color
Color.
facets.title_bg_padding number
Padding. Horizontal space between text and background
facets_hide_empty boolean
Hide empty charts when filtering.
Colors
color.categorical_palette colors
Palette.
color.categorical_extend boolean
Extend. Automatically generate additional colours when needed to avoid the palette colours being used more than once.
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:
Party 1: red
Party 2: #4455AA
Party 3: rgb(30,168,26)
color.numeric_type string
Scale type. Allowed values:
color.binning boolean
In linear mode, the color scale will run as a smooth gradient between 2 colors. In binned mode, the gradient will be divided in smaller blocks. Allowed values:
color.bin_mode string
Binning mode. Allowed values:
color.bin_count number
Number of bins.
color.bin_thresholds string
Custom thresholds. Write your custom thresholds, separated by a ";" For example "5;10;15". Bins are created between the domain minimum and the first threshold, between each threshold and between the final threshold and the domain maximum. Therefore for the example "5;10;15" four bins are created. (The domain is the minimum and maximum values of your data.)
color.sequential_palette string
Palette. Allowed values:
color.sequential_reverse boolean
Reverse.
color.sequential_custom_min color
Minimum color.
color.sequential_custom_max color
Maximum color.
color.sequential_color_space string
Color space. Allowed values:
color.sequential_custom_domain boolean
Domain. Allowed values:
color.sequential_domain_min number
Min.
color.sequential_domain_max number
Max.
color.diverging_palette string
Palette. Allowed values:
color.diverging_reverse boolean
Reverse.
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
Color space. Allowed values:
color.diverging_custom_domain boolean
Domain. Allowed values:
color.diverging_domain_min number
Min.
color.diverging_domain_mid number
Mid.
color.diverging_domain_max number
Max.
link_opacity number
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
Position. Allowed values:
label_outwards_max_width number
Space. The max space available for the labels, as a percentage of total width Max: 40
label_color_mode string
Color mode. Allowed values:
label_color color
Color.
label_bold boolean
Bold.
label_show_values boolean
Include values.
label_show_values_links string
Show link values. Allowed values:
label_color_links color
Colour.
label_outline boolean
Outline. Allowed values:
label_outline_width number
Width. As a percent of the font size Max: 100
label_font_size number
Font size. In rems, a multiple of base font size Max: 3
label_facet_scaling boolean
Scale with grid. Sets a max size based on the facet size, regardless of the page width
Step headings
show_node_headings boolean
Show headings. Enables the labels above each "column" of nodes an Alluvial diagram
node_headings_bold boolean
Bold.
node_headings_font_size number
Font size.
node_headings_padding number
Padding.
node_headings_max_width number
Max width.
node_headings_color color
Controls
filter_controls.control_type string
Control type. Choose between a dropdown, buttons or a time slider. Allowed values:
filter_controls.control_styles boolean
Adv..
filter_controls.control_title string
Control title.
filter_controls.button_group boolean
Grouped. Allowed values:
filter_controls.button_group_width_mode string
Button group width. Allowed values:
filter_controls.button_group_width_fixed number
Width. Max: 100
filter_controls.dropdown_width_mode string
Dropdown width. Allowed values:
filter_controls.dropdown_width_fixed number
Width. Max: 100
filter_controls.slider_width number
Slider width. Width of the slider track. In rems, multiples of base font size. Max: 100
filter_controls.slider_max_label_width number
Max label width. In rems, multiples of base font size. If larger than the longest label, only the space required to fit labels will be used. Max: 100
filter_controls.slider_step_time number
Time between steps. Measured in seconds, positive values move the slider left to right, negative values move the slider right to left. Min: -100 Max: 100
filter_controls.slider_loop boolean
Loop.
filter_controls.slider_restart_pause number
Pause before loop. Measured in seconds and in addition to the regular step time displayed above. Max: 100
filter_controls.sort boolean
Sorting. Allowed values:
filter_show_all boolean
Include "All".
filter_show_all_text string
“All” label.
controls_style.font_size number
Text size. Max: 5
controls_style.font_weight string
Text weight. Allowed values:
controls_style.height number
Height. Max: 5
dropdown_style.background color
Background.
dropdown_style.font_color color
Text color.
dropdown_style.border_styles_advanced boolean
Dropdown border styles.
dropdown_style.border_style string
Border style. Show border on all sides, or only at the bottom Allowed values:
dropdown_style.border_width number
Border width. Max: 20
dropdown_style.border_color color
Color.
dropdown_style.border_transparency number
Transparency. Max: 1
dropdown_style.border_radius number
Radius. Max: 100
button_style.background color
Background.
button_style.background_selected color
Selected.
button_style.background_hover color
Mouse over.
button_style.font_color color
Text color.
button_style.font_color_selected color
Selected.
button_style.font_color_hover color
Mouse over.
button_style.button_styles_advanced boolean
Button border styles.
button_style.border_width number
Border width. Max: 20
button_style.border_color color
Color.
button_style.border_transparency number
Transparency. Max: 1
button_style.border_radius number
Radius. Max: 100
slider_style.track_color color
Track.
slider_style.font_color color
Text.
slider_style.handle_color color
Handle.
slider_style.play_color color
Play/pause.
slider_style.track_height number
Track height. Max: 1
slider_style.handle_height number
Height. Max: 10
slider_style.play_button boolean
Play button.
Animations
intro_duration number
Duration.
intro_ease_range number
Speed variation. When set at zero, all the links are revealed at an even speed. When set above zero, the lines randomly accelerate and decelerate slightly to give a more natural effect. Max: 100
transition_duration number
Duration. In seconds
Number formatting
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.advanced boolean
Advanced.
formatting.negative_sign string
Styling of negative numbers. Allowed values:
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
Main font. This font will apply to the whole graphic by default, but you can optionally change the font for the title, subtitle, footer, etc in the Header and Footer settings panels.
layout.font_color color
Text color. This color will apply to the whole graphic by default, but you can optionally change the color for individual text elements, in other settings panels.
layout.background_color_enabled boolean
Color. Allowed values:
layout.background_image_enabled boolean
Image. Allowed values:
layout.background_color color
Background color.
layout.background_image_src url
Image URL.
layout.background_image_size string
Size. Allowed values:
layout.background_image_position string
Position. Allowed values:
layout.max_width_target string
Maximum width. Apply a maximum width to just the main graphic or everything (main graphic plus header, footer, etc) Allowed values:
layout.max_width number
Maximum width. Leave blank to stretch to container width Min: 50
layout.max_width_align string
Align. Allowed values:
layout.layout_order string
Layout order. Allowed values:
layout.space_between_sections string
Space between sections. Allowed values:
layout.space_between_sections_custom number
Custom. Max: 100
layout.margin_top number
Top.
layout.margin_right number
Right.
layout.margin_bottom number
Bottom.
layout.margin_left number
Left.
layout.border.enabled boolean
Show borders around visualisation.
layout.border.top.width number
Top.
layout.border.top.style string
Style. Allowed values:
layout.border.top.color color
Color.
layout.border.right.width number
Right.
layout.border.right.style string
Style. Allowed values:
layout.border.right.color color
Color.
layout.border.bottom.width number
Bottom.
layout.border.bottom.style string
Style. Allowed values:
layout.border.bottom.color color
Color.
layout.border.left.width number
Left.
layout.border.left.style string
Style. Allowed values:
layout.border.left.color color
Color.
layout.read_direction string
Read direction. This will change the reading direction of the main text elements on the page. Its not possible to adjust this on all elements such as axes. Note that when direction is set to "right to left" any alignment icons will be reversed. Allowed values:
Header
layout.header_align string
Alignment. Allowed values:
layout.title html
layout.title_styling boolean
Styling.
layout.title_font font
Title Font.
layout.title_size string
Size. Allowed values:
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:
layout.title_color color
Color.
layout.title_line_height number
Line height. Max: 3
layout.title_space_above string
Space above. Allowed values:
layout.title_space_above_custom number
Custom. Max: 100
layout.subtitle html
layout.subtitle_styling boolean
Styling.
layout.subtitle_font font
Subtitle Font.
layout.subtitle_size string
Size. Allowed values:
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:
layout.subtitle_color color
Color.
layout.subtitle_line_height number
Line height. Max: 3
layout.subtitle_space_above string
Space above. Allowed values:
layout.subtitle_space_above_custom number
Custom. Max: 100
layout.header_text html
layout.header_text_styling boolean
Styling.
layout.header_text_size string
Size. Allowed values:
layout.header_text_size_custom number
Custom. Specify a custom responsive font size. Best results will be with values between 1.2 and 3
layout.header_text_weight string
Weight. Allowed values:
layout.header_text_color color
Color.
layout.header_text_line_height number
Line height. Max: 3
layout.header_text_space_above string
Space above. Allowed values:
layout.header_text_space_above_custom number
Custom. Max: 100
layout.header_border string
Allowed values:
- top (Top)
- bottom (Bottom)
- top_and_bottom (Top & bottom)
- none (None)
layout.header_border_width number
Width.
layout.header_border_color color
Color.
layout.header_border_style string
Style. Allowed values:
layout.header_border_space number
Space. Space between border and header text
layout.header_logo_enabled boolean
Allowed values:
- true (Enabled)
- false (Disabled)
layout.header_logo_src url
Image.
layout.header_logo_link_url string
Link.
layout.header_logo_height number
Height.
layout.header_logo_align string
Align. Align logo inside either the header or the main visualisation container Allowed values:
layout.header_logo_position_inside string
Position. Allowed values:
layout.header_logo_position_outside string
Position. Allowed values:
layout.header_logo_margin_top number
Top.
layout.header_logo_margin_right number
Right.
layout.header_logo_margin_bottom number
Bottom.
layout.header_logo_margin_left number
Left.
Footer
layout.footer_align string
Alignment. Allowed values:
layout.footer_text_size number
Size.
layout.footer_text_color color
Color.
layout.footer_styling boolean
Advanced footer styles.
layout.footer_font font
Font.
layout.footer_text_weight string
Weight. Allowed values:
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.footer_note string
Note.
layout.footer_note_secondary string
Note (secondary). The secondary note is placed below the source and primary note
layout.footer_logo_enabled boolean
Image. Allowed values:
layout.footer_logo_src url
Image.
layout.footer_logo_src_light hidden
Image (light version). If provided this version will be used whenever the background colour is dark
layout.footer_logo_link_url string
Link.
layout.footer_logo_height number
Height.
layout.footer_logo_margin number
Margin.
layout.footer_logo_order string
Position. Allowed values:
layout.footer_align_vertical string
V. align. Allowed values:
layout.footer_border string
Allowed values:
- top (Top)
- bottom (Bottom)
- top_and_bottom (Top & bottom)
- none (None)
layout.footer_border_width number
Width.
layout.footer_border_color color
Color.
layout.footer_border_style string
Style. Allowed values:
layout.footer_border_space number
Space. Space between border and footer text
Accessibility
layout.screenreader_hide_primary boolean
Screenreader mode for main visual container. Whether the main visual container is visible to screenreaders. (Text in the header and footer are always available to screenreaders.) Allowed values:
layout.screenreader_text_primary text
Screenreader description. A text alternative to the visual content that will only be visible to screenreaders, e.g. “The line chart shows China consistently higher than the other countries since 1990”. Do not replicate your title, since that will also be read by screenreaders.
layout.screenreader_label string
Screenreader label. A short text label given to the main Flourish embed wrapper to provide an accessible name that is only visible to screenreaders. Added in the form of an "aria-label".
