Package Exports

s-haversine

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Readme

s-haversine

Dependencies

About

This module calculates the distance between two points on Earth using lat/long coordinates. It is based on the haversine formula and includes a utility to convert from degrees/minutes/seconds to the signed decimal degrees format needed for the formula to work.

This is great for use with the html5 geolocation api, which provides lat/long coordinates.

Usage

Get a pair of latitude/longitude coordinates (eg. from the geolocation api), then use them as the arguments for the distance method. Example:

var haversine = require('s-haversine');

// ---------- [latitude, longitude];
var coords1 = [36.151829, -115.143296];
var coords2 = [36.151465, -115.146284];

haversine.distance(coords1, coords2); // 271.314... (meters)

Converting deg/min/sec to decimal

This module requires coordinates to be in a signed decimal format. If you have coordinates in degrees/minutes/seconds format, use the toDecimal method to convert them. For example, an input such as 40 20 50W or 40°20'50" S will return roughly -40.34722.

haversine.toDecimal('40 20 50W'); // -40.34722... (degrees)

Earth radius

The math involved in the haversine formula depends on knowledge of the Earth's radius. This is configured by default as 6371000 (in meters). If you need to fine tune this or use another radius, you can configure this by setting haversine.earthRadius to a number before calling the distance method.