Wind Rose Chart

Mix.install([
  {:plotly_ex, "~> 0.3"},
  {:kino, "~> 0.18"}
])

Section

A wind rose uses Barpolar traces to show directional frequency data. r: contains the magnitude (e.g. frequency or speed), theta: contains compass directions as strings or degree values. Multiple Barpolar traces show different speed categories stacked by direction.

alias Plotly.{Figure, Barpolar}

directions = ["N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE",
              "S", "SSW", "SW", "WSW", "W", "WNW", "NW", "NNW"]

# Frequencies (%) for each direction, two speed categories
slow = [5.0, 1.5, 1.5, 2.2, 2.0, 2.0, 5.0, 4.0,
        6.0, 5.0, 4.0, 4.0, 3.0, 2.5, 4.0, 4.0]
fast = [2.0, 0.5, 0.5, 0.8, 1.0, 1.0, 2.0, 1.5,
        3.0, 2.5, 2.0, 1.5, 1.5, 1.5, 2.0, 2.0]

Figure.new()
|> Figure.add_trace(
  Barpolar.new(
    r: slow,
    theta: directions,
    name: "< 5 m/s",
    marker: %{color: "steelblue"}
  )
)
|> Figure.add_trace(
  Barpolar.new(
    r: fast,
    theta: directions,
    name: "> 5 m/s",
    marker: %{color: "firebrick"}
  )
)
|> Figure.update_layout(
  title: "Wind Rose Chart",
  polar: %{
    radialaxis: %{ticksuffix: "%", angle: 45, dtick: 2},
    angularaxis: %{direction: "clockwise"}
  }
)
|> Plotly.show()