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;
    }