Contour Line Labels

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

Section

contours: %{showlabels: true} prints the z value on each contour line. contours: %{labelfont: %{size:, color:, family:}} styles these labels. Works best when combined with coloring: "fill" or coloring: "heatmap".

alias Plotly.{Figure, Contour}

z = for i <- 0..19 do
  for j <- 0..19 do
    :math.sin(i * :math.pi() / 10) * :math.cos(j * :math.pi() / 10)
  end
end

Figure.new()
|> Figure.add_trace(
  Contour.new(
    z: z,
    colorscale: "Viridis",
    contours: %{
      showlabels: true,
      labelfont: %{size: 12, color: "white"}
    }
  )
)
|> Figure.update_layout(title: "Contour Plot with Line Labels")
|> Plotly.show()