tinyplot (version 0.6.0)

type_area: Ribbon and area plot types

Description

Type constructor functions for producing polygon ribbons, which define a y interval (usually spanning from ymin to ymax) for each x value. Area plots are a special case of ribbon plot where ymin is set to 0 and ymax is set to y.

Usage

type_area(alpha = NULL)
type_ribbon(alpha = NULL, dodge = 0, fixed.dodge = FALSE)

Arguments

alpha

numeric value between 0 and 1 specifying the opacity of ribbon shading If no alpha value is provided, then will default to tpar("ribbon.alpha") (i.e., probably 0.2 unless this has been overridden by the user in their global settings.)

dodge

Adjustment parameter for dodging overlapping points or ranges in grouped plots along the x-axis (or y-axis for flipped plots). Either:

• numeric value in the range [0,1). Note that values are scaled relative to the spacing of x-axis breaks, e.g. dodge = 0.1 places the outermost groups one-tenth of the way to adjacent breaks, dodge = 0.5 places them midway between breaks, etc. Values < 0.5 are recommended.

• logical. If TRUE, the dodge width is calculated automatically based on the number of groups (0.1 per group for 2-4 groups, 0.45 for 5+ groups). If FALSE or 0, no dodging is performed.

Default value is 0 (no dodging). While we do not check, it is strongly recommended that dodging only be used in cases where the x-axis comprises a limited number of discrete breaks.

fixed.dodge

Logical. If FALSE (default), dodge positions are calculated independently for each x value, based only on the groups present at that position. If TRUE, dodge positions are based on all groups, ensuring "fixed" spacing across x-axis breaks (i.e., even if some groups are missing for a particular x value).

Dodging ribbon plots

We support dodging for grouped ribbon plots, enabling similar functionality to dodged errorbar and pointrange plots. However, it is strongly recommended that dodging is only implemented for cases where the x-axis comprises a limited number of discrete cases (e.g., coefficient or event-study plots). See Examples.

Examples

x = 1:100 / 10
y = sin(x)

#
## Ribbon plots

# "ribbon" convenience string
tinyplot(x = x, ymin = y - 1, ymax = y + 1, type = "ribbon")
# Same result with type_ribbon()
tinyplot(x = x, ymin = y-1, ymax = y+1, type = type_ribbon())

# y will be added as a line if it is specified
tinyplot(x = x, y = y, ymin = y-1, ymax = y+1, type = "ribbon")

#
## Area plots

# "area" type convenience string
tinyplot(x, y, type = "area")

# Same result with type_area()
tinyplot(x, y, type = type_area())

# Area plots are often used for time series charts
tinyplot(AirPassengers, type = "area")

#
## Dodged ribbon/area plots

# Dodged ribbon or area plots can be useful in cases where there is strong
# overlap across groups (and a limited number of discrete x-axis values).

dat = data.frame(
  x = rep(c("Before", "After"), each = 2),
  grp = rep(c("A", "B"), 2),
  y = c(10, 10.5, 15, 15.3),
  lwr = c(8, 8.5, 13, 13.3),
  upr = c(12, 12.5, 17, 17.3)
)

tinyplot(
  y ~ x | grp,
  data = dat,
  ymin = lwr, ymax = upr,
  type = type_ribbon(),
  main = "Overlappling ribbons"
)

tinyplot(
  y ~ x | grp,
  data = dat,
  ymin = lwr, ymax = upr,
  type = type_ribbon(dodge = 0.1),
  main = "Dodged ribbons"
)