/**
 * Classification methods for choropleth maps.
 *
 * `'quantile'` puts an equal *count* of features in each class — good when the
 * data is skewed and you want every class populated. `'equal-interval'` splits
 * the *value range* evenly — good when the numbers themselves are the story and
 * empty classes are meaningful. Choosing wrongly is the most common way a
 * choropleth misleads, so the method is always explicit, never inferred.
 */
export type MapClassifyMethod = 'quantile' | 'equal-interval';
export interface MapClass {
    /** Inclusive lower bound. */
    min: number;
    /** Upper bound: exclusive, except on the last class where it is inclusive. */
    max: number;
    /** Zero-based position, used to index into the color ramp. */
    index: number;
}
/**
 * Splits values into `steps` classes.
 *
 * Returns fewer classes than requested when the data cannot support more — a
 * single distinct value yields one class rather than a stack of empty
 * degenerate ranges. Non-finite values are ignored, and an empty input yields
 * no classes at all (the caller should then paint everything as "no data").
 */
export declare function classifyValues(values: number[], steps: number, method?: MapClassifyMethod): MapClass[];
/** Index of the class a value belongs to, or `-1` when it belongs to none. */
export declare function classIndexOf(value: number, classes: MapClass[]): number;
/**
 * Interpolates a ramp of `count` colors through the given stops.
 *
 * Choropleth ramps are declared as two or three tokens (`['--chart-2', '--destructive']`)
 * but need one color per class, so the intermediate shades are mixed here rather
 * than asking the consumer to name every step.
 */
export declare function interpolateRamp(stops: string[], count: number): string[];
/** Default label for a class, e.g. `"12 – 48"`. */
export declare function formatClassLabel(mapClass: MapClass, digits?: number): string;