Scatter Tile Maps — Adding Lines

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

Section

mode: "lines" connects lat/lon points in sequence — useful for routes, tracks, or boundaries. Separate traces create separate line segments.

alias Plotly.{Figure, Scattermap}

# US cross-country routes
routes = [
  {[40.7128, 39.7392, 34.0522], [-74.0060, -104.9903, -118.2437], "NYC → Denver → LA", "blue"},
  {[41.8781, 35.2271, 29.7604], [-87.6298, -80.8431, -95.3698], "Chicago → Charlotte → Houston", "red"},
  {[47.6062, 45.5051, 37.7749], [-122.3321, -122.6750, -122.4194], "Seattle → Portland → SF", "green"}
]

fig = Figure.new()

fig =
  Enum.reduce(routes, fig, fn {lats, lons, name, color}, acc ->
    Figure.add_trace(acc,
      Scattermap.new(
        lat: lats,
        lon: lons,
        mode: "lines+markers",
        name: name,
        line: %{width: 2, color: color},
        marker: %{size: 8}
      )
    )
  end)

fig
|> Figure.update_layout(
  title: "US Routes on Tile Map",
  map: %{
    style: "open-street-map",
    center: %{lat: 39.0, lon: -98.0},
    zoom: 3
  }
)
|> Plotly.show()