Radius scale (area-proportional bubble size)

Maps the data value to the circle radius, so perceived bubble area grows quadratically with the value – the correct encoding for magnitude comparisons (Vega-Lite's scaleRadius). Where scale_size() maps to ggplot2's area-like size unit linearly, scale_radius() emphasizes relative magnitudes.

Usage

scale_radius(
  plot,
  name = ggplot2::waiver(),
  trans = "identity",
  limits = NULL,
  range = NULL,
  breaks = NULL,
  labels = NULL,
  ...
)

Arguments

plot: A plotit object.
name: Scale title (legend name).
trans: Scale transformation. Default "identity". Allowed: "identity", "log", "log10", "log2", "sqrt", "reverse". Discrete/binned routes are rejected with guidance toward scale_size().
limits: Data domain.
range: Output radius range as c(min, max). NULL = default c(1, 6).
breaks: Legend key positions.
labels: Legend key labels.
...: Passed to the underlying ggplot2 scale function.

Value

A modified plotit object.

References

Vega-Lite: Radius

Examples

plotit(
  ggplot2::midwest,
  encode(x = popdensity, y = percollege, size = poptotal)
) |>
  mark_point(alpha = 0.5) |>
  scale_radius(range = c(1, 10))