{
  "$schema": "https://vega.github.io/schema/vega-lite/v2.json",
  "data": { "url": "data/cars.csv" },
  "mark": "rect",
  "encoding": {
    "x": {"field": "make", "type": "nominal", "axis": {"title": "Make"}},
    "y": {"field": "body-style", "type": "nominal", "axis": {"title": "Body Style"}},
    "color": {"aggregate": "count", "type": "quantitative"}
  },
  "config": {
    "background":"#ffffff",    
    "range": {
      "heatmap": {
        "scheme": "greenblue"
      }
    }
  }
}