quantile1.vl

{
    "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
    "data": {
        "url": "https://vega.github.io/vega-lite/data/normal-2d.json"
    },
    "hconcat": [
        {
            "encoding": {
                "x": {
                    "field": "unif",
                    "type": "quantitative"
                },
                "y": {
                    "field": "v",
                    "type": "quantitative"
                }
            },
            "mark": "point"
        },
        {
            "encoding": {
                "x": {
                    "field": "norm",
                    "type": "quantitative"
                },
                "y": {
                    "field": "v",
                    "type": "quantitative"
                }
            },
            "mark": "point"
        }
    ],
    "transform": [
        {
            "as": [
                "p",
                "v"
            ],
            "quantile": "u",
            "step": 1.0e-2
        },
        {
            "as": "unif",
            "calculate": "quantileUniform(datum.p)"
        },
        {
            "as": "norm",
            "calculate": "quantileNormal(datum.p)"
        }
    ]
}