/
index.js
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/
index.js
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var distance = require('turf-distance');
/**
* Takes a reference {@link Point|point} and a set of points and returns the point from the set closest to the reference.
*
* @module turf/nearest
* @category classification
* @param {Feature<Point>} point the reference point
* @param {FeatureCollection<Point>} against input point set
* @return {Feature<Point>} the closest point in the set to the reference point
* @example
* var point = {
* "type": "Feature",
* "properties": {
* "marker-color": "#0f0"
* },
* "geometry": {
* "type": "Point",
* "coordinates": [28.965797, 41.010086]
* }
* };
* var against = {
* "type": "FeatureCollection",
* "features": [
* {
* "type": "Feature",
* "properties": {},
* "geometry": {
* "type": "Point",
* "coordinates": [28.973865, 41.011122]
* }
* }, {
* "type": "Feature",
* "properties": {},
* "geometry": {
* "type": "Point",
* "coordinates": [28.948459, 41.024204]
* }
* }, {
* "type": "Feature",
* "properties": {},
* "geometry": {
* "type": "Point",
* "coordinates": [28.938674, 41.013324]
* }
* }
* ]
* };
*
* var nearest = turf.nearest(point, against);
* nearest.properties['marker-color'] = '#f00';
*
* var resultFeatures = against.features.concat(point);
* var result = {
* "type": "FeatureCollection",
* "features": resultFeatures
* };
*
* //=result
*/
module.exports = function(targetPoint, points) {
var nearestPoint;
points.features.forEach(function(pt) {
if(!nearestPoint) {
nearestPoint = pt;
var dist = distance(targetPoint, pt, 'miles');
nearestPoint.properties.distance = dist;
} else {
var dist = distance(targetPoint, pt, 'miles');
if(dist < nearestPoint.properties.distance) {
nearestPoint = pt;
nearestPoint.properties.distance = dist;
}
}
});
delete nearestPoint.properties.distance;
return nearestPoint;
};