legend3.vl

{
    "height": 300,
    "mark": "circle",
    "data": {
        "url": "https://vega.github.io/vega-lite/data/cars.json"
    },
    "width": 300,
    "$schema": "https://vega.github.io/schema/vega-lite/v3.json",
    "encoding": {
        "color": {
            "field": "Origin",
            "type": "nominal",
            "legend": {
                "orient": "top-right"
            }
        },
        "size": {
            "field": "Horsepower",
            "type": "quantitative",
            "legend": {
                "orient": "top-right"
            }
        },
        "opacity": {
            "field": "Weight_in_lbs",
            "type": "quantitative",
            "legend": {
                "orient": "top-right"
            }
        },
        "x": {
            "field": "Horsepower",
            "type": "quantitative"
        },
        "y": {
            "field": "Miles_per_Gallon",
            "type": "quantitative"
        }
    }
}