Styled 2D Histogram Contour

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

Section

contours: %{showlines: false} removes the contour outlines, leaving only the fill. line: %{width: 0} achieves the same result when using the line key. Overlaying a Scatter on top shows individual data points within the density map.

alias Plotly.{Figure, Histogram2dcontour, Scatter}

:rand.seed(:exsss, {1, 2, 3})

gen = fn n ->
  for _ <- 1..n do
    (for _ <- 1..12, do: :rand.uniform()) |> Enum.sum() |> Kernel.-(6.0)
  end
end

n = 300
x = gen.(n)
y = gen.(n)

Figure.new()
|> Figure.add_trace(
  Histogram2dcontour.new(
    x: x,
    y: y,
    colorscale: "Blues",
    ncontours: 15,
    contours: %{showlines: false}
  )
)
|> Figure.add_trace(
  Scatter.new(
    x: x,
    y: y,
    mode: "markers",
    marker: %{color: "rgba(255,255,255,0.5)", size: 3},
    showlegend: false
  )
)
|> Figure.update_layout(title: "Styled 2D Histogram Contour")
|> Plotly.show()