Contour Lines

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

Section

contours: %{coloring: "lines"} renders only the contour lines, colour-coded by value using the chosen colorscale:. The fill is transparent. Combine with line: %{width: 2} to make the lines more visible.

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: "Jet",
    contours: %{coloring: "lines"},
    line: %{width: 2}
  )
)
|> Figure.update_layout(title: "Contour Lines Only (coloring: \"lines\")")
|> Plotly.show()