Errorbar

Layers are declared with the DRAW clause. Read the documentation for this clause for a thorough description of how to use it.

Errorbars are used to display paired metrics, typically some interval, for a variable. It is displayed as a line between the two values, often with hinges at the ends.

Aesthetics

The following aesthetics are recognised by the errorbar layer.

Required

x or y: Position on the x- or y-axis. These are mutually exclusive.
xmin or ymin: Position of one of the interval ends orthogonal to the main position. These are also mutually exclusive.
xmax or ymax: Position of the other interval end orthogonal to the main position. These are also mutually exclusive.

Note that the required aesthetics is either a set of {x, ymin, ymax} or {y, xmin, xmax} and not a combination of the two.

Optional

stroke/colour: The colour of the lines in the errorbar.
opacity: The opacity of the colour.
linewidth: The width of the lines in the errorbar.
linetype: The dash pattern of the lines in the errorbar.

Settings

width: The width of the hinges in points. Can be set to null to not display hinges.

Data transformation

The errorbar layer does not transform its data but passes it through unchanged.

Examples

Create example data

CREATE TABLE penguin_summary AS
SELECT
  species,
  MEAN(bill_dep) - STDDEV(bill_dep) AS low,
  MEAN(bill_dep) AS mean,
  MEAN(bill_dep) + STDDEV(bill_dep) AS high
FROM ggsql:penguins
GROUP BY species

Classic errorbar with point at centre.

VISUALISE species AS x FROM penguin_summary
  DRAW errorbar MAPPING low AS ymax, high AS ymin
  DRAW point MAPPING mean AS y

Dynamite plot using bars instead of points, using extra wide hinges.

VISUALISE species AS x FROM penguin_summary
  DRAW errorbar 
    MAPPING low AS ymax, high AS ymin
    SETTING width => 40
  DRAW bar MAPPING mean AS y

The hinges can be omitted by setting null as width.

VISUALISE species AS x FROM penguin_summary
  DRAW errorbar 
    MAPPING low AS ymax, high AS ymin
    SETTING width => null