{ "$schema": "https://vega.github.io/schema/vega-lite/v4.json", "description": "Area chart showing weight of cars over time (vertical).", "data": {"url": "data/cars.json"}, "mark": { "type": "area", "interpolate": "monotone" }, "encoding": { "x": {"aggregate": "sum", "field": "Weight_in_lbs"}, "y": {"timeUnit": "year", "field": "Year"} }}