contraction-hierarchy-js/src/coordinateLookup.js

Contraction Hierarchy

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


export function CoordinateLookup(graph) {

  if (!graph._geoJsonFlag) {
    throw new Error('Cannot use Coordinate Lookup on a non-GeoJson network.');
  }

  const points_set = new Set();

  Object.keys(graph._nodeToIndexLookup).forEach(key => {
    points_set.add(key);
  });

  const coordinate_list = [];

  points_set.forEach(pt_str => {
    coordinate_list.push(pt_str.split(',').map(d => Number(d)));
  });

  this.coordinate_list = coordinate_list; // Store for lookup
  this.index = new kdbush(coordinate_list.length);
  for (const coord of coordinate_list) {
    this.index.add(coord[0], coord[1]);
  }
  this.index.finish();
}

CoordinateLookup.prototype.getClosestNetworkPt = function(lng, lat) {
  const closestIndex = geokdbush.around(this.index, lng, lat, 1)[0];
  return this.coordinate_list[closestIndex];
};

export const __geoindex = geokdbush;
export const __kdindex = kdbush;