Hexagonal bins: geom_hex

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

About this notebook

This notebook follows the examples on ggplot2's reference page for geom_hex(), which covers stat_bin_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.

geom_hex() is a heatmap of counts in two dimensions: its stat, stat_bin_hex(), divides the plane into regular hexagons and counts the rows that fall in each, and the count is mapped to the hexagon's fill. Hexagons avoid the artefacts the strict alignment of square bins (geom_bin_2d()) can produce. The size of the bins is set by their number or their width, for x and y together or each on its own. Giggly has none of this yet.

Counting in hexagons

d <- ggplot(diamonds, aes(carat, price))
d + geom_hex()

Each hexagon's count is mapped to its fill, so the plot has a legend for the counts.

Not in Giggly yet: geom_hex().

The number of bins

# You can control the size of the bins by specifying the number of
# bins in each direction:
d + geom_hex(bins = 10)
d + geom_hex(bins = 30)

Not in Giggly yet: geom_hex() and its bins option.

The width of the bins

# Or by specifying the width of the bins
d + geom_hex(binwidth = c(1, 1000))
d + geom_hex(binwidth = c(.1, 500))

A pair of widths gives the width along x first, then along y.

Not in Giggly yet: geom_hex() and its binwidth option.