Quantile Transform

The quantile transform ≥ 5.7 calculates empirical quantile values for an input data stream. If a groupby parameter is provided, quantiles are estimated separately per group. Among other uses, the quantile transform is useful for creating quantile-quantile (Q-Q) plots.

Transform Parameters

Property Type Description
field Field Required. The data field for which to perform quantile estimation.
groupby Field[ ] The data fields to group by. If not specified, a single group containing all data objects will be used.
probs Number[ ] An array of probabilities in the range (0, 1) for which to compute quantile values. If not specified, the step parameter will be used.
step Number A probability step size (default 0.01) for sampling quantile values. All values from one-half the step size up to 1 (exclusive) will be sampled. This parameter is only used if the probs parameter is not provided.
as String[ ] The output fields for the probability and quantile value. The default is ["prob", "value"].


This example computes the quartile boundaries for the input data field value:

{"type": "quantile", "field": "value", "probs": [0.25, 0.50, 0.75]}

This example computes 20 equally-spaced quantiles (from 0.025 to 0.975):

{"type": "quantile", "field": "value", "step": 0.05}

For more, see the quantile-quantile plot example.