Calculate distance in meters when you know longitude and latitude in java [duplicate]

Question

Possible Duplicate:
Working with latitude/longitude values in Java

Duplicate:

• Working with latitude/longitude values in Java
• How do I calculate distance between two latitude longitude points?

I need to calculate the distance between two points given by two coordinates. The project I am working on is a Java-project, so Java-code will be great, but pseudo-code can also be given, then I can implement it myself :)

As you probably know, there are three ways to represent coordinates:

• Degrees:Minutes:Seconds (49°30'00"N, 123°30'00"W)
• Degrees:Decimal Minutes (49°30.0', -123°30.0'), (49d30.0m,-123d30.0')
• Decimal Degrees (49.5000°,-123.5000°), generally with 4-6 decimal numbers.

It's the third way my coordinates are given in, so the code for this values will be preferred :)

Answer 1

Based on another question on stackoverflow, I got this code.. This calculates the result in meters, not in miles :)

 public static float distFrom(float lat1, float lng1, float lat2, float lng2) {     double earthRadius = 6371000; //meters     double dLat = Math.toRadians(lat2-lat1);     double dLng = Math.toRadians(lng2-lng1);     double a = Math.sin(dLat/2) * Math.sin(dLat/2) +                Math.cos(Math.toRadians(lat1)) * Math.cos(Math.toRadians(lat2)) *                Math.sin(dLng/2) * Math.sin(dLng/2);     double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));     float dist = (float) (earthRadius * c);      return dist;     } 

Answer 2

You can use the Java Geodesy Library for GPS, it uses the Vincenty's formulae which takes account of the earths surface curvature.

Implementation goes like this:

import org.gavaghan.geodesy.*;  ...  GeodeticCalculator geoCalc = new GeodeticCalculator();  Ellipsoid reference = Ellipsoid.WGS84;    GlobalPosition pointA = new GlobalPosition(latitude, longitude, 0.0); // Point A  GlobalPosition userPos = new GlobalPosition(userLat, userLon, 0.0); // Point B  double distance = geoCalc.calculateGeodeticCurve(reference, userPos, pointA).getEllipsoidalDistance(); // Distance between Point A and Point B 

The resulting distance is in meters.