Summaries in 2d bins: stat_summary_2d

Mix.install([
  {:giggly, path: Path.join(__DIR__, "..")},
  {:kino, "~> 0.19"}
  ])

About this notebook

This notebook follows the examples on ggplot2's reference page for stat_summary_2d(), which covers stat_summary_hex() too, in the order the page gives them. Each example shows ggplot2's code first and then Giggly's. An example Giggly cannot draw yet keeps its ggplot2 code and names what it is waiting for, so the page is also a list of what remains.

stat_summary_2d() divides the panel into rectangular bins by x and y, summarises the values of z that fall in each bin with a function, the mean by default, and draws each bin as a tile filled by its summary. stat_summary_hex() does the same with hexagonal bins. They are the two-dimensional form of stat_summary(). Giggly has none of it yet.

The mean in each bin

d <- ggplot(diamonds, aes(carat, depth, z = price))
d + stat_summary_2d()

Each tile's fill is the mean price of the diamonds in its bin.

Not in Giggly yet: mapping z, stat_summary_2d() and the tiles it draws, and geom_tile().

Choosing the summary

R takes the summary function in several forms: an anonymous function, a formula, a function's name, or a string naming it, with fun.args passing it further arguments.

# Specifying function
d + stat_summary_2d(fun = \(x) sum(x^2))
d + stat_summary_2d(fun = ~ sum(.x^2))
d + stat_summary_2d(fun = var)
d + stat_summary_2d(fun = "quantile", fun.args = list(probs = 0.1))

Not in Giggly yet: mapping z, stat_summary_2d() and its fun and fun.args options, and geom_tile().

Hexagonal bins

These examples run only where R's hexbin package, which computes hexagonal bins, is installed.

if (requireNamespace("hexbin")) {
d + stat_summary_hex()
d + stat_summary_hex(fun = ~ sum(.x^2))
}

Not in Giggly yet: mapping z, stat_summary_hex() and its fun option, the hexagons it draws, and geom_hex().