compute-distance

Find the distance associated with an array of geospatial coordinates.

There are three methods associated with this library. Each takes an options param, where you can pass your Google Maps API object (using this library, for example).

filter(data, options)

A filter designed to smooth abberations from a GPS trace. It discards coordinates with accuracy less than 20 meters and coordinates that are more than 20 meters from their nearest neighbor.

Each object in the array should have the following attributes set:

{
  longitude: Double,
  latitude: Double,
  accuracy: Double // optional
}

mapToGoogle(data, options)

Take an array of coordinates and convert them to google.maps.LatLng objects.

Each object in the array should have the following attributes set:

{
  longitude: Double,
  latitude: Double
}

computeDistance(data, options)

Take an array of google.maps.LatLng objects and compute the distance they represent in meters.

Usage

This library depends on the Google Maps Javascript API, so be sure to include it using the directions on this page.

To filter a set of data before computing distance, use the following code:

var Distance = require('compute-distance');
var GoogleMapsLoader = require('google-maps');
GoogleMapsLoader.KEY = 'your-api-key';
GoogleMapsLoader.LIBRARIES = ['geometry'];

GoogleMapsLoader.load(function(google) {
  var options = { google: google };
  var filtered = Distance.filter(data, options); // data is an array of coordinates
  var points = Distance.mapToGoogle(filtered, options);
  var distance = Distance.computeDistance(points, options);
};

To compute distance on a raw dataset, without filtering, pass your raw data to mapToGoogle directly, instead of passing it through filter first.