Size scale

Declare the scale for a mapped size aesthetic: data values map linearly to a point-size range (in mm). A size legend is drawn automatically.

scale_size_area() maps the data value to the marker's area rather than its radius, with value 0 at size 0 — the perceptually honest default for bubble charts (a value twice as large looks twice as big in ink). max_size is the size (mm) of the largest value.

Usage

scale_size(plot, range = NULL, limits = NULL, breaks = NULL, name = NULL)

scale_size_area(plot, max_size = 6, limits = NULL, breaks = NULL, name = NULL)

Arguments

plot

A PlotSpec.

range

Numeric length-2 output size range in mm, or NULL for the default c(1, 4).

limits

Numeric length-2 data domain, or NULL to train from the data.

breaks

Explicit legend breaks, or NULL.

name

Legend title, or NULL to derive from the encoding.

max_size

For scale_size_area(), the point size (mm) of the largest value.

Value

The modified PlotSpec.

Examples

vplot(mtcars) |> mark_point(x = wt, y = mpg, size = hp) |> scale_size(range = c(1, 8))

vplot(mtcars) |>
  mark_point(x = wt, y = mpg, size = hp) |>
  scale_size_area(max_size = 10)