raster_montana.vg.json

{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "description": "",
  "width": 1200,
  "height": 300,
  "autosize": {
    "type": "fit-x",
    "resize": false
  },

  "signals": [
    {
      "name": "scale", "value": 5000
    },
    {
      "name": "opacity", "value": 0.75,
      "bind": {"input": "range", "min": 0.25, "max": 1, "step": 0.05}
    },
    {
      "name": "backgroundopacity", "value": 0.75,
      "bind": {"input": "range", "min": 0.4, "max": 1, "step": 0.05}
    },
    {
      "name": "levels", "value": 3,
      "bind": {"input": "range", "min": 2, "max": 4, "step": 1}
    },
    {
      "name": "stop", "value": 2
    },
    {
      "name": "step",
      "update": "stop / levels"
    }

  ],

  "data": [
    {
      "name": "population",
      "url": "data/montana_native.json"
    },
    {
      "name": "contours",
      "source": "population",
      "transform": [
        {
          "type": "isocontour",
          "thresholds": {"signal": "sequence(0.0000001, stop, step)"}
        }
      ]
    },
    {
      "name": "montana",
      "url": "data/montana.json"
    }
  ],

  "projections": [
    {
      "name": "projection",
      "type": "albersUsa",
      "translate": [1300, 1000],
      "center": [450, 260],
      "scale": {"signal": "scale"}
    }
  ],

  "scales": [
    {
      "name": "color",
      "type": "quantize",
      "domain": {"signal": "[0, stop]"},
      "range": {"scheme": "custom", "count": {"signal": "levels"}}
    }
  ],

  "marks": [
    {
      "type": "shape",
      "clip": false,
      "from": {
        "data": "montana"
      },
      "encode": {
        "update": {
          "strokeWidth": {
            "value": 2
          },
          "stroke": {
            "value": "#ffffff"
          },
          "fill": {
            "value": "#51647d"
          },
          "fillOpacity": {"signal": "backgroundopacity"}
        }
      },
      "transform": [
        {
          "type": "geoshape",
          "projection": "projection"
        }
      ]
    },
    {
      "type": "shape",
      "from": { "data": "contours"},
      "encode": {
        "update": {
          "fill": {"scale": "color", "field": "contour.value"},
          "fillOpacity": {"signal": "opacity"}
        }
      },
      "transform": [
        {
          "type": "geoshape",
          "field": "datum.contour",
          "projection": "projection"
        }
      ]
    }
  ],

  "legends": [
    {
      "title": "2010 American Indian Population (%)",
      "orient": "left",
      "offset": 0,
      "type": "gradient",
      "direction": "vertical",
      "gradientLength": 200,
      "gradientThickness": 25,
      "titlePadding": 10,
      "titleOrient": "left",
      "titleAnchor": "middle",
      "titleLineHeight": 20,
      "titleBaseline": "line-top",
      "titleFontSize": 10,
      "fill": "color"
    }
  ],
  "config": {
    "legend": {"layout": {"anchor": "middle"}}
  }
}