{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "background": "white",
  "padding": 5,
  "width": 500,
  "height": 300,
  "data": [
    {
      "name": "source_1",
      "url": "data/unemployment.tsv",
      "format": {"type": "tsv"}
    },
    {
      "name": "source_0",
      "url": "data/us-10m.json",
      "format": {"type": "topojson", "feature": "counties"},
      "transform": [
        {
          "type": "lookup",
          "from": "source_1",
          "key": "id",
          "fields": ["id"],
          "values": ["rate"]
        },
        {
          "type": "filter",
          "expr": "isValid(datum[\"rate\"]) && isFinite(+datum[\"rate\"])"
        }
      ]
    }
  ],
  "projections": [
    {
      "name": "projection",
      "size": {"signal": "[width, height]"},
      "fit": {"signal": "data('source_0')"},
      "type": "albersUsa"
    }
  ],
  "marks": [
    {
      "name": "marks",
      "type": "shape",
      "style": ["geoshape"],
      "from": {"data": "source_0"},
      "encode": {
        "update": {
          "fill": {"scale": "color", "field": "rate"},
          "ariaRoleDescription": {"value": "geoshape"},
          "description": {
            "signal": "\"rate: \" + (format(datum[\"rate\"], \"\"))"
          }
        }
      },
      "transform": [{"type": "geoshape", "projection": "projection"}]
    }
  ],
  "scales": [
    {
      "name": "color",
      "type": "linear",
      "domain": {"data": "source_0", "field": "rate"},
      "range": "heatmap",
      "interpolate": "hcl",
      "zero": false
    }
  ],
  "legends": [
    {
      "fill": "color",
      "gradientLength": {"signal": "clamp(height, 64, 200)"},
      "title": "rate"
    }
  ]
}