geokdbush

geokdbush

A geographic extension for KDBush, the fastest static spatial index for points in JavaScript.

It implements fast nearest neighbors queries for locations on Earth, taking Earth curvature and date line wrapping into account. Inspired by sphere-knn, but uses a different algorithm.

Example

import KDBush from 'kdbush';
import * as geokdbush from 'geokdbush';

const index = new KDBush(points.length);
for (conts {lon, lat} of points) index.add(lon, lat);
index.finish();

const nearestIds = geokdbush.around(index, -119.7051, 34.4363, 1000);

const nearest = nearestIds.map(id => points[id]);

API

geokdbush.around(index, longitude, latitude[, maxResults, maxDistance, filterFn])

Returns an array of the closest points from a given location in order of increasing distance.

• index: kdbush index.
• longitude: query point longitude.
• latitude: query point latitude.
• maxResults: (optional) maximum number of points to return (Infinity by default).
• maxDistance: (optional) maximum distance in kilometers to search within (Infinity by default).
• filterFn: (optional) a function to filter the results with.

geokdbush.distance(longitude1, latitude1, longitude2, latitude2)

Returns great circle distance between two locations in kilometers.

Performance

This library is incredibly fast. The results below were obtained with npm run bench (Node v20, Macbook Pro 2020 M1 Pro).

benchmark	geokdbush	sphere-knn	naive
index 138398 points	57.6ms	408ms	n/a
query 1000 closest	1.6ms	1.8ms	72ms
query 50000 closest	14.7ms	91.5ms	72ms
query all 138398	33.7ms	500ms	72ms
1000 queries of 1	24.7ms	27.5ms	11.1s