Basic Filled Ternary Plot

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

Section

fill: "toself" on a Scatterternary trace closes the polygon and fills the interior. Use this to create filled regions (e.g. classification zones) in ternary space. Each trace is one filled region. Close the polygon by repeating the first point at the end.

alias Plotly.{Figure, Scatterternary}

# Three soil classification zones as filled polygons
zones = [
  %{
    name: "Clay zone",
    a: [0.0, 0.0, 0.2, 0.4, 0.0],
    b: [0.0, 0.4, 0.4, 0.2, 0.0],
    c: [1.0, 0.6, 0.4, 0.4, 1.0],
    color: "rgba(205, 133, 63, 0.4)"
  },
  %{
    name: "Sand zone",
    a: [0.8, 1.0, 1.0, 0.8, 0.8],
    b: [0.0, 0.0, 0.0, 0.2, 0.0],
    c: [0.2, 0.0, 0.0, 0.0, 0.2],
    color: "rgba(245, 222, 179, 0.4)"
  },
  %{
    name: "Silt zone",
    a: [0.0, 0.2, 0.2, 0.0, 0.0],
    b: [0.8, 0.6, 0.8, 1.0, 0.8],
    c: [0.2, 0.2, 0.0, 0.0, 0.2],
    color: "rgba(107, 142, 35, 0.4)"
  }
]

fig =
  Enum.reduce(zones, Figure.new(), fn zone, fig ->
    Figure.add_trace(fig,
      Scatterternary.new(
        a: zone.a,
        b: zone.b,
        c: zone.c,
        mode: "lines",
        fill: "toself",
        fillcolor: zone.color,
        line: %{color: "black", width: 1},
        name: zone.name
      )
    )
  end)

fig
|> Figure.update_layout(
  title: "Basic Filled Ternary Plot (Classification Zones)",
  ternary: %{
    aaxis: %{title: "Sand"},
    baxis: %{title: "Silt"},
    caxis: %{title: "Clay"}
  }
)
|> Plotly.show()