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https://github.com/Turfjs/turf.git
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e5afd5c38b
* Simplify nx config (no point separately caching es and js builds - they both need to be done for any code changes). Fix some no-op type definitions i.e. X extends any, and enforce templated property types as having to extend GeoJsonProperties throughout. * Upgrade typescript. Had to update topojson-* type defs to avoid the P = GeoJsonProperties problem in geojson-rbush. Also fix a couple of floating point precision related issues that eslint now apparently catches! * Retire tslint. * Upgrade eslint and prettier. Add minimal prettier config (defaults have changed) to avoid widespread, minor formatting changes (trailing commas mostly).
96 lines
3.2 KiB
TypeScript
96 lines
3.2 KiB
TypeScript
import {
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BBox,
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Feature,
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Polygon,
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MultiPolygon,
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FeatureCollection,
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Point,
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GeoJsonProperties,
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} from "geojson";
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import within from "@turf/boolean-within";
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import distance from "@turf/distance";
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import { point, featureCollection, Units } from "@turf/helpers";
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/**
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* Creates a {@link Point} grid from a bounding box, {@link FeatureCollection} or {@link Feature}.
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*
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* @name pointGrid
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* @param {Array<number>} bbox extent in [minX, minY, maxX, maxY] order
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* @param {number} cellSide the distance between points, in units
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* @param {Object} [options={}] Optional parameters
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* @param {string} [options.units='kilometers'] used in calculating cellSide, can be degrees, radians, miles, or kilometers
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* @param {Feature<Polygon|MultiPolygon>} [options.mask] if passed a Polygon or MultiPolygon, the grid Points will be created only inside it
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* @param {Object} [options.properties={}] passed to each point of the grid
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* @returns {FeatureCollection<Point>} grid of points
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* @example
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* var extent = [-70.823364, -33.553984, -70.473175, -33.302986];
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* var cellSide = 3;
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* var options = {units: 'miles'};
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*
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* var grid = turf.pointGrid(extent, cellSide, options);
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*
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* //addToMap
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* var addToMap = [grid];
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*/
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function pointGrid<P extends GeoJsonProperties = GeoJsonProperties>(
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bbox: BBox,
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cellSide: number,
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options: {
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units?: Units;
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mask?: Feature<Polygon | MultiPolygon>;
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properties?: P;
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} = {}
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): FeatureCollection<Point, P> {
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// Default parameters
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if (options.mask && !options.units) options.units = "kilometers";
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// Containers
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var results = [];
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// Typescript handles the Type Validation
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// if (cellSide === null || cellSide === undefined) throw new Error('cellSide is required');
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// if (!isNumber(cellSide)) throw new Error('cellSide is invalid');
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// if (!bbox) throw new Error('bbox is required');
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// if (!Array.isArray(bbox)) throw new Error('bbox must be array');
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// if (bbox.length !== 4) throw new Error('bbox must contain 4 numbers');
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// if (mask && ['Polygon', 'MultiPolygon'].indexOf(getType(mask)) === -1) throw new Error('options.mask must be a (Multi)Polygon');
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var west = bbox[0];
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var south = bbox[1];
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var east = bbox[2];
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var north = bbox[3];
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var xFraction = cellSide / distance([west, south], [east, south], options);
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var cellWidth = xFraction * (east - west);
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var yFraction = cellSide / distance([west, south], [west, north], options);
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var cellHeight = yFraction * (north - south);
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var bboxWidth = east - west;
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var bboxHeight = north - south;
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var columns = Math.floor(bboxWidth / cellWidth);
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var rows = Math.floor(bboxHeight / cellHeight);
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// adjust origin of the grid
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var deltaX = (bboxWidth - columns * cellWidth) / 2;
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var deltaY = (bboxHeight - rows * cellHeight) / 2;
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var currentX = west + deltaX;
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while (currentX <= east) {
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var currentY = south + deltaY;
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while (currentY <= north) {
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var cellPt = point([currentX, currentY], options.properties);
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if (options.mask) {
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if (within(cellPt, options.mask)) results.push(cellPt);
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} else {
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results.push(cellPt);
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}
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currentY += cellHeight;
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}
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currentX += cellWidth;
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}
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return featureCollection(results);
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}
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export default pointGrid;
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