multi8.vl

{
    "transform": [
        {
            "as": "time",
            "calculate": "hours(datum.date) + minutes(datum.date) / 60"
        }
    ],
    "data": {
        "url": "https://vega.github.io/vega-lite/data/flights-5k.json",
        "format": {
            "parse": {
                "date": "date"
            }
        }
    },
    "vconcat": [
        {
            "height": 100,
            "mark": "bar",
            "width": 963,
            "selection": {
                "brush": {
                    "init": {
                        "x": [
                            6,
                            12
                        ]
                    },
                    "encodings": [
                        "x"
                    ],
                    "type": "interval"
                }
            },
            "encoding": {
                "x": {
                    "field": "time",
                    "bin": {
                        "maxbins": 30
                    },
                    "type": "quantitative"
                },
                "y": {
                    "aggregate": "count",
                    "type": "quantitative"
                }
            }
        },
        {
            "height": 100,
            "mark": "bar",
            "width": 963,
            "encoding": {
                "x": {
                    "field": "time",
                    "bin": {
                        "maxbins": 30,
                        "extent": {
                            "selection": "brush"
                        }
                    },
                    "type": "quantitative"
                },
                "y": {
                    "aggregate": "count",
                    "type": "quantitative"
                }
            }
        }
    ],
    "$schema": "https://vega.github.io/schema/vega-lite/v4.json"
}