{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "background": "white",
  "padding": 5,
  "width": 500,
  "height": 300,
  "data": [
    {
      "name": "source_0",
      "url": "data/us-10m.json",
      "format": {"type": "topojson", "feature": "states"}
    },
    {
      "name": "source_1",
      "url": "data/airports.csv",
      "format": {"type": "csv"},
      "transform": [
        {
          "type": "geojson",
          "fields": ["longitude", "latitude"],
          "signal": "layer_1_geojson_0"
        },
        {
          "type": "geopoint",
          "projection": "projection",
          "fields": ["longitude", "latitude"],
          "as": ["layer_1_x", "layer_1_y"]
        }
      ]
    }
  ],
  "projections": [
    {
      "name": "projection",
      "size": {"signal": "[width, height]"},
      "fit": {"signal": "[data('source_0'), layer_1_geojson_0]"},
      "type": "albersUsa"
    }
  ],
  "marks": [
    {
      "name": "layer_0_marks",
      "type": "shape",
      "style": ["geoshape"],
      "from": {"data": "source_0"},
      "encode": {
        "update": {
          "fill": {"value": "lightgray"},
          "stroke": {"value": "white"},
          "ariaRoleDescription": {"value": "geoshape"}
        }
      },
      "transform": [{"type": "geoshape", "projection": "projection"}]
    },
    {
      "name": "layer_1_marks",
      "type": "symbol",
      "style": ["circle"],
      "from": {"data": "source_1"},
      "encode": {
        "update": {
          "opacity": {"value": 0.7},
          "fill": {"value": "steelblue"},
          "ariaRoleDescription": {"value": "circle"},
          "description": {
            "signal": "\"longitude: \" + (format(datum[\"longitude\"], \"\")) + \"; latitude: \" + (format(datum[\"latitude\"], \"\"))"
          },
          "x": {"field": "layer_1_x"},
          "y": {"field": "layer_1_y"},
          "size": {"value": 10},
          "shape": {"value": "circle"}
        }
      }
    }
  ]
}