import { Grid, Units } from '@turf/helpers';
import { FeatureCollection, Point, BBox, Polygon } from 'geojson';

/**
 * Takes a set of points and estimates their 'property' values on a grid using the [Inverse Distance Weighting (IDW) method](https://en.wikipedia.org/wiki/Inverse_distance_weighting).
 *
 * @function
 * @param {FeatureCollection<Point>} points with known value
 * @param {number} cellSize the distance across each grid point
 * @param {Object} [options={}] Optional parameters
 * @param {string} [options.gridType='square'] defines the output format based on a Grid Type (options: 'square' | 'point' | 'hex' | 'triangle')
 * @param {string} [options.property='elevation'] the property name in `points` from which z-values will be pulled, zValue fallbacks to 3rd coordinate if no property exists.
 * @param {Units} [options.units='kilometers'] used in calculating cellSize. Supports all valid Turf {@link https://turfjs.org/docs/api/types/Units Units}.
 * @param {number} [options.weight=1] exponent regulating the distance-decay weighting
 * @param {BBox}   [options.bbox=bbox(points)] Bounding Box Array [west, south, east, north] associated with the FeatureCollection.
 * @returns {FeatureCollection<Point|Polygon>} grid of points or polygons with interpolated 'property'
 * @example
 * var points = turf.randomPoint(30, {bbox: [50, 30, 70, 50]});
 *
 * // add a random property to each point
 * turf.featureEach(points, function(point) {
 *     point.properties.solRad = Math.random() * 50;
 * });
 * var options = {gridType: 'points', property: 'solRad', units: 'miles'};
 * var grid = turf.interpolate(points, 100, options);
 *
 * //addToMap
 * var addToMap = [grid];
 */
declare function interpolate<T extends Grid = "square">(points: FeatureCollection<Point>, cellSize: number, options?: {
    gridType?: T;
    property?: string;
    units?: Units;
    weight?: number;
    bbox?: BBox;
}): FeatureCollection<T extends "point" ? Point : Polygon>;

export { interpolate as default, interpolate };