interaction5.vl

{
    "mark": "point",
    "data": {
        "url": "https://vega.github.io/vega-lite/data/cars.json"
    },
    "$schema": "https://vega.github.io/schema/vega-lite/v3.json",
    "selection": {
        "myPaintbrush": {
            "nearest": true,
            "type": "multi",
            "on": "mouseover"
        }
    },
    "encoding": {
        "size": {
            "value": 50,
            "condition": {
                "value": 300,
                "selection": "myPaintbrush"
            }
        },
        "x": {
            "field": "Horsepower",
            "type": "quantitative"
        },
        "y": {
            "field": "Miles_per_Gallon",
            "type": "quantitative"
        }
    },
    "description": "Mouse over individual points or select multiple points with the shift key"
}