Polar Chart Sector

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

Section

layout.polar.sector: [start_deg, end_deg] restricts the visible angular range, creating a partial (sector) polar chart instead of a full circle. [0, 180] creates a semicircle; [0, 90] creates a quarter circle.

alias Plotly.{Figure, Scatterpolar}

theta = Enum.map(0..18, fn i -> i * 10 end)
r     = Enum.map(theta, fn t -> 1 + :math.sin(t * :math.pi() / 180 * 2) end)

Figure.new()
|> Figure.add_trace(
  Scatterpolar.new(
    r: r,
    theta: theta,
    mode: "lines+markers",
    fill: "toself",
    name: "Upper semicircle"
  )
)
|> Figure.update_layout(
  title: "Polar Chart Sector — Upper Half (0° to 180°)",
  polar: %{
    sector: [0, 180],
    radialaxis: %{range: [0, 2.5]}
  }
)
|> Plotly.show()