Vega spec from Mon Jan 25 2021

spec.json

{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "width": 900,
  "height": 560,
  "padding": {"top": 0, "left": 0, "right": 0, "bottom": 0},
  "signals": [],
  "data": [  {
  "name": "airports",
  "url": "data/airports.csv",
  "format": {"type": "csv", "parse": "auto"},
  "transform": [
    {
      "type": "geopoint",
      "projection": "projection",
      "fields": ["longitude", "latitude"]
    },
    {
      "type": "filter",
      "expr": "datum.x != null && datum.y != null"
    }
  ]
},{
    "name": "states",
    "url": "data/us-10m.json",
    "format": {"type": "topojson", "feature": "states"},
    "transform": [
      {
        "type": "geopath",
        "projection": "projection"
      }
    ]
  }],
  "scales": [],
  "projections": [  {
    "description":"project map x y to longitude latitude, different type of projection",
    "name": "projection",
    "type": "albersusa",
    "scale": 1200,
    "translate": [{"signal": "width / 2"}, {"signal": "height / 2"}]
  }],
"marks": [
  {
    "type": "path",
    "from": {"data": "states"},
    "encode": {
      "enter": {
        "fill": {"value": "#dedede"},
        "stroke": {"value": "white"}
      },
      "update": {
        "path": {"field": "path"}
      }
    }
  },
  {
  "type": "symbol",
  "from": {"data": "airports"},
  "encode": {
    "enter": {
      "size": {"value": 16},
      "fill": {"value": "steelblue"},
      "fillOpacity": {"value": 0.8},
      "stroke": {"value": "white"},
      "strokeWidth": {"value": 1.5}
    },
    "update": {
      "x": {"field": "x"},
      "y": {"field": "y"}
    }
  }
}
]
}