Error Band

// Single View Specification{  "data": ... ,  "mark": "errorband",  "encoding": ... ,  ...}

An error band summarizes an error range of quantitative values using a set of summary statistics, representing by area. Error band in Vega-Lite can either be used to aggregate raw data or directly visualize aggregated data.

To create an error band, setmark to"errorband".

Documentation Overview

• Error Band Mark Properties
• Comparing the usage of Error Band to the usage of Error Bar
  • Error Band
  • Error Bar
• Using Error Band to Aggregate Raw Data
• Using Error Band to Visualize Aggregated Data
• Dimension
• The Parts of Error Band
• Color, and Opacity Encoding Channels
• Tooltip Encoding Channels
• Mark Config

Error Band Mark Properties

An error band’s mark definition can contain the following properties:

Besides the properties listed above,band andborders can be used to specify the underlyingmark properties for differentparts of the error band as well.

Comparing the usage of Error Band to the usage of Error Bar

All the properties and usage of error band are identical to error bar’s, except theband andborders that replace the error bar’srule andticks.

Error Band

Error Bar

Using Error Band to Aggregate Raw Data

If the data is not aggregated yet, Vega-Lite will aggregate the data based on theextent properties in the mark definition as done in theerror band showing confidence interval above. All otherextent values are defined inError Bar.

Using Error Band to Visualize Aggregated Data

1. Data is aggregated with low and high values of the error band

If the data is already pre-aggregated with low and high values of the error band, you can directly specifyx andx2 (ory andy2) to use error band as a ranged mark.

1. Data is aggregated with center and error value(s)

If the data is already pre-aggregated with center and error values of the error band, you can usex/y,x/yError, andx/yError2 as defined inError Bar

Dimension

Vega-Lite supports both 1D and 2D error bands:

{:#1d} A1D error band shows the error range of a continuous field; it can be used to show the global error range of the whole plot.

{:#2d} A2D error band shows the error range of a continuous field for each dimension value such as year.

The Parts of Error Band

Under the hood, theerrorband mark is acomposite mark that expands into a layered plot. For example,the basic 2D error band shown above is equivalent to:

We can customize different parts of the error bandmark definition orconfig.

For example, we can add the error band’s borders and customize it by settingborders totrue or adding a mark property toborders, such asstrokeDash andopacity:

Color, and Opacity Encoding Channels

You can customize the color, size, and opacity of the band in theerrorband by using thecolor, andopacityencoding channels, which applied to the wholeerrorband.

Here is an example of aerrorband with thecolor encoding channel set to{"value": "black"}.

Tooltip Encoding Channels

You can add custom tooltips to error bands. The custom tooltip will override the default error band’s tooltips.

Mark Config

{  "errorband": {    "extent": ...,    "band": ...,    "borders": ...  }}

Theerrorband config object sets the default properties forerrorband marks.

The error band config can contain allerror band mark properties but currently not supportingcolor,opacity, andorient. Please see issue#3934.