com.github.gwtd3.api.scales

Class QuantileScale

java.lang.Object

com.google.gwt.core.client.JavaScriptObject

com.github.gwtd3.api.scales.Scale<S>

com.github.gwtd3.api.scales.QuantitativeScale<S>

com.github.gwtd3.api.scales.DiscreteQuantitativeScale<QuantileScale>

com.github.gwtd3.api.scales.QuantileScale

public class QuantileScale
extends DiscreteQuantitativeScale<QuantileScale>

Quantile scales map an input domain to a discrete range.

Although the input domain is continuous and the scale will accept any reasonable input value, the input domain is specified as a discrete set of values.

The number of values in (the cardinality of) the output range determines the number of quantiles that will be computed from the input domain. To compute the quantiles, the input domain is sorted, and treated as a population of discrete values. The input domain is typically a dimension of the data that you want to visualize, such as the daily change of the stock market. The output range is typically a dimension of the desired output visualization, such as a diverging color scale.

A new quantile scale is invalid until both a domain and range are specified.

The input domain of the quantile scale is a set of discrete numeric values.

The input domain array must not be empty, and must contain at least one numeric value; NaN, null and undefined values are ignored and not considered part of the sample population.

If the elements in the given array are not numbers, they will be coerced to numbers; this coercion happens similarly when the scale is called.

A copy of the input array is sorted and stored internally. Thus, a quantile scale can be used to encode any type that can be converted to numbers.

The output range array must not be empty, and may contain any type of value. The number of values in (the cardinality, or length, of) the values array determines the number of quantiles that are computed. For example, to compute quartiles, values must be an array of four elements such as [0, 1, 2, 3].

Author:

Anthony Schiochet

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	QuantileScale()

Method Summary

Methods

Modifier and Type	Method and Description
Array<Double>	quantiles() Returns the quantile thresholds.

Methods inherited from class com.github.gwtd3.api.scales.DiscreteQuantitativeScale

invertExtent, invertExtent

Methods inherited from class com.github.gwtd3.api.scales.Scale

apply, apply, apply, copy, domain, domain, domain, domain, range, range, range, range

Methods inherited from class com.google.gwt.core.client.JavaScriptObject

cast, createArray, createArray, createFunction, createObject, equals, hashCode, toSource, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

QuantileScale

protected QuantileScale()

Method Detail

quantiles

public final Array<Double> quantiles()

Returns the quantile thresholds.

If the output range contains n discrete values, the returned threshold array will contain n - 1 values. Values less than the first element in the thresholds array, quantiles()[0], are considered in the first quantile; greater values less than the second threshold are in the second quantile, and so on.

Internally, the thresholds array is used with D3#bisect to find the output quantile associated with the given input value.

Returns:

the array of threshold values