geoflatbush

A geographic extension for flatbush, a very fast static 2D spatial index. Performs nearest neighbors queries for geographic bounding boxes, taking Earth curvature and date line wrapping into account. Similar to geokdbush, but for boxes instead of points.

import {around} from 'geoflatbush';

around(index, 30.5, 50.5, 10); // return 10 nearest boxes to Kyiv

API

around(index, lng, lat[, maxResults, maxDistance, filterFn])

Returns an array of item indices from the given Flatbush index in order of geographical distance from the given lng, lat point (known as K nearest neighbors, or KNN).

const ids = around(index, 30.5, 50.5, 5); // returns 5 ids around Kyiv

maxResults and maxDistance are Infinity by default. maxDistance is assumed in kilometers.

If given a filterFn, calls it on items that potentially belong to the results (passing the item's index) and only includes an item if the function returned a truthy value.

distance(lng, lat, lng2, lat2)

Returns the geographical distance between two given points in kilometers using the Haversine distance formula.