Choropleth Map of 2014 US Population by State

Mix.install([
  {:plotly_ex, "~> 0.3"},
  {:kino, "~> 0.18"},
  {:req, "~> 0.5"}
])

Section

US population data by state, with colorscale: "YlOrRd" for population intensity.

alias Plotly.{Figure, Choropleth}

url = "https://raw.githubusercontent.com/plotly/datasets/master/2014_usa_states.csv"
body = Req.get!(url).body

[header | rows] = String.split(body, "\n", trim: true)
keys = String.split(header, ",") |> Enum.map(&String.trim/1)

data =
  rows
  |> Enum.map(fn row ->
    values = String.split(row, ",")
    Enum.zip(keys, values) |> Map.new()
  end)
  |> Enum.reject(&(&1["Postal"] == "" or is_nil(&1["Postal"])))

states = Enum.map(data, & &1["Postal"])
pop = Enum.map(data, &round(elem(Float.parse(&1["Population"]), 0)))
text = Enum.map(data, fn r -> "#{r["State"]}: #{r["Population"]}" end)

Figure.new()
|> Figure.add_trace(
  Choropleth.new(
    locations: states,
    z: pop,
    text: text,
    locationmode: "USA-states",
    colorscale: "YlOrRd",
    colorbar: %{title: %{text: "Population"}},
    hoverinfo: "text"
  )
)
|> Figure.update_layout(
  title: "2014 US Population by State",
  geo: %{
    scope: "usa",
    showland: true,
    landcolor: "#EAEAAE"
  }
)
|> Plotly.show()