Horserace chart

A ‘horserace’ or ‘bumps’ chart, useful to show changing rank over time

Updated 2 years ago by Template retirement home

How to use this template

Horserace chart

A simple charting template for plotting changing rank in a group of competitors over time. Useful for showing the changing fortunes of candidates in elections, football team, etc.

Data requirements

Each row after the header row should be a participant in the race – such as a politician or team. There should be a column for the participant name and multiple columns for the “stages” in the race (week, day, hours, etc). Each stage is plotted at an equal width on the chart.

Credits and feedback

Created by Duncan Clark, Daan Louter and Robin Houston, originally based on a design by Google News Lab. Want to see additional features? Let us know at support@flourish.studio (or submit a pull request).

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

template: _123

version: _15

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:

    {
        horserace: [
            { "HorseraceHeader1": ..., "HorseraceHeader2": ..., ... },
            { "HorseraceHeader1": ..., "HorseraceHeader2": ..., ... },
            { "HorseraceHeader1": ..., "HorseraceHeader2": ..., ... },
            ...
        ]
    }

... 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: "_123",
    version: "_15",
    bindings: {
        horserace: {
            name: "HorseraceHeader1"
        }
    },
    data: {
        horserace: [
            { "HorseraceHeader1": ..., "HorseraceHeader2": ..., ... },
            { "HorseraceHeader1": ..., "HorseraceHeader2": ..., ... },
            { "HorseraceHeader1": ..., "HorseraceHeader2": ..., ... },
            ...
        ]
    }
}

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

{
    template: "_123",
    version: "_15",
    bindings: {
        horserace: {
            name: "HorseraceHeader1",
            pic: "HorseraceHeader2",
            stages: ["HorseraceHeader3", "HorseraceHeader4", ...]
        }
    },
    data: {
        horserace: [
            { "HorseraceHeader1": ..., "HorseraceHeader2": ..., ... },
            { "HorseraceHeader1": ..., "HorseraceHeader2": ..., ... },
            { "HorseraceHeader1": ..., "HorseraceHeader2": ..., ... },
            ...
        ]
    }
}

(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: "_123",
version: "_15",
data: {
    horserace: [
        {
            name: ...,
            stages: [...]
        },
        ...
    ]
},
...
}

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

{
template: "_123",
version: "_15",
data: {
    horserace: [
        {
            name: ...,
            pic: ...,
            stages: [...]
        },
        ...
    ]
},
...
}

Meanings of the template data keys:

  • horserace.name: The name of each entrant
  • horserace.pic: The URL of the image to use
  • horserace.stages: Raw scores, which will be automatically converted to ranks. Column names will be used to populate the x-axis of the chart.

Template settings

Options for opts.state.

Scoring type

value_type string

Show ranks by default.

Allowed values:

  • ranks (Ranks)
  • scores (Scores)

target_position number

Default start stage. Which stage the graphic should "play" to by default

Min: 1

higher_scores_win boolean

Higher scores win. Uncheck this if lower scores beat higher scores (eg. race times)

show_buttons boolean

Allow users to switch between modes.

Line styles

line_width number

Line width.

line_opacity number

Line opacity.

curve string

Curve.

Allowed values:

  • curveLinear (Straight)
  • curveMonotoneX (Normal curve)
  • curveNatural (Overflowing curve)
  • curveStep (Step middle)
  • curveStepAfter (Step after)
  • curveStepBefore (Step before)

shade boolean

Show shading behind line.

shade_width number

Shading width.

shade_opacity number

Shading opacity.

Circles and labels

start_circle_r number

Start radius.

end_circle_r number

End radius.

rank_font_size number

Rank font size.

label_font_size number

Label font size.

label_decimals number

No of decimal places on scores.

rank_label_suffix string

Suffix.

horse_images boolean

Use image.

rank_outside_picture boolean

Move score outside picture.

Colors

bg_color color

Background color.

palette string

Color scheme. Choose "Other" to specify a comma-separate list of colour names or codes, or the name of a d3-chromatic scheme such as schemeAccent

Allowed values:

  • schemeCategory10 (Category 10)
  • schemeCategory20 (Category 20)
  • schemeCategory20b (Category 20b)
  • schemeCategory20c (Category 20c)
  • schemeAccent (Accent)
  • schemeDark2 (Dark 2)
  • schemePaired (Paired)
  • schemePastel1 (Pastel 1)
  • schemePastel2 (Pastel 2)

custom_colors text

Custom colors. Override the colour scheme by entering a comma-separated list of colors names or codes

Animation

stage_duration number

Animation duration. The "race" animation length in milliseconds per stage

update_duration number

Mode duration. The animation duration when change between ranks and scores modes

Margins

margin_top number

Top.

margin_right number

Right.

margin_bottom number

Bottom.

margin_left number

Left.

Y axis

y_axis_min number

Min score value.

y_axis_max number

Max score value.

y_axis_tick_suffix string

Suffix score label.