--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gnv-artifacts/src/main/java/de/intevation/gnv/utils/DistanceCalculator.java	Fri Oct 16 12:37:00 2009 +0000
@@ -0,0 +1,65 @@
+/**
+ *
+ */
+package de.intevation.gnv.utils;
+
+import com.vividsolutions.jts.geom.Point;
+
+/**
+ * @author Tim Englich <tim.englich@intevation.de>
+ *
+ */
+public class DistanceCalculator {
+
+    private final static double flattening = 1.0 / 298.257233563;
+    
+    private final static double earthRadius = 6378137.0 / 1000.0 ;
+    
+    /**
+     * Constructor
+     */
+    public DistanceCalculator() {
+    }
+    
+    public double calculateDistance(Point p1, Point p2){
+        double resultValue = 0.0;
+        
+        double b1 = p1.getY();
+        double b2 = p2.getY();
+        
+        double l1 = p1.getX();
+        double l2 = p2.getX();
+        
+        
+        double F = (b1 + b2) / 2.0;
+        double G = (b1 - b2) / 2.0;
+        double l = (l1 - l2) / 2.0;
+        
+        F = (Math.PI / 180.0) * F;
+        G = (Math.PI / 180.0) * G;
+        l = (Math.PI / 180.0) * l;
+        
+        double S = ((Math.sin(G) * Math.sin(G)) * ((Math.cos(l) * Math.cos(l))))+
+                   ((Math.cos(F) * Math.cos(F)) * ((Math.sin(l) * Math.sin(l))));
+        
+        double C = ((Math.cos(G) * Math.cos(G)) * ((Math.cos(l) * Math.cos(l))))+
+                   ((Math.sin(F) * Math.sin(F)) * ((Math.sin(l) * Math.sin(l))));
+        
+        double w = Math.atan(Math.sqrt((S/C)));
+        
+        double D = 2.0 * w * earthRadius;
+        
+        double R = Math.sqrt((S*C)) / w;
+        
+        double H1 = (3.0 * R - 1.0 ) / (2.0 * C);
+        double H2 = (3.0 * R + 1.0 ) / (2.0 * S);
+        
+        resultValue = D * (1 + (flattening * H1 * (Math.sin(F) * Math.sin(F)) * 
+                                                  (Math.cos(G) * Math.cos(G))) - 
+                           (flattening * H2 * (Math.cos(F) * Math.cos(F)) * 
+                                              (Math.sin(G) * Math.sin(G))));
+        
+        return resultValue;
+    }
+
+}