12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849 |
- import clone from "@turf/clone";
- import distance from "@turf/distance";
- import { featureEach } from "@turf/meta";
- /**
- * Takes a reference {@link Point|point} and a FeatureCollection of Features
- * with Point geometries and returns the
- * point from the FeatureCollection closest to the reference. This calculation
- * is geodesic.
- *
- * @name nearestPoint
- * @param {Coord} targetPoint the reference point
- * @param {FeatureCollection<Point>} points against input point set
- * @returns {Feature<Point>} the closest point in the set to the reference point
- * @example
- * var targetPoint = turf.point([28.965797, 41.010086], {"marker-color": "#0F0"});
- * var points = turf.featureCollection([
- * turf.point([28.973865, 41.011122]),
- * turf.point([28.948459, 41.024204]),
- * turf.point([28.938674, 41.013324])
- * ]);
- *
- * var nearest = turf.nearestPoint(targetPoint, points);
- *
- * //addToMap
- * var addToMap = [targetPoint, points, nearest];
- * nearest.properties['marker-color'] = '#F00';
- */
- function nearestPoint(targetPoint, points) {
- // Input validation
- if (!targetPoint)
- throw new Error("targetPoint is required");
- if (!points)
- throw new Error("points is required");
- var nearest;
- var minDist = Infinity;
- var bestFeatureIndex = 0;
- featureEach(points, function (pt, featureIndex) {
- var distanceToPoint = distance(targetPoint, pt);
- if (distanceToPoint < minDist) {
- bestFeatureIndex = featureIndex;
- minDist = distanceToPoint;
- }
- });
- nearest = clone(points.features[bestFeatureIndex]);
- nearest.properties.featureIndex = bestFeatureIndex;
- nearest.properties.distanceToPoint = minDist;
- return nearest;
- }
- export default nearestPoint;
|