Spokes: geom_spoke

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_spoke(), 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_spoke() is geom_segment() described by a direction and a distance: each row's segment starts at its x and y and runs radius in the direction angle, in radians, measured anticlockwise from east. It suits data that records a direction and a distance, such as movement or wind. Giggly has none of this yet.

A spoke at each point

R's expand.grid() makes a 10 by 10 grid of points, and runif() gives each a random angle, and a random speed whose upper limit grows with x.

df <- expand.grid(x = 1:10, y=1:10)

set.seed(1)
df$angle <- runif(100, 0, 2*pi)
df$speed <- runif(100, 0, sqrt(0.1 * df$x))

ggplot(df, aes(x, y)) +
  geom_point() +
  geom_spoke(aes(angle = angle), radius = 0.5)

Not in Giggly yet: geom_spoke(), mapping angle, and a fixed radius.

Spokes of different lengths

ggplot(df, aes(x, y)) +
  geom_point() +
  geom_spoke(aes(angle = angle, radius = speed))

Not in Giggly yet: geom_spoke(), and mapping angle and radius.