First commit.

Haversine.h

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+//
+//  haversine.h
+//
+//  Created by Carsten Nielsen on 23/04/09.
+//
+
+#import <Foundation/Foundation.h>
+
+extern float const HAVERSINE_RADS_PER_DEGREE;
+extern float const HAVERSINE_MI_RADIUS;
+extern float const HAVERSINE_KM_RADIUS;
+extern float const HAVERSINE_M_PER_KM;
+extern float const HAVERSINE_F_PER_MI;
+
+@interface Haversine : NSObject {
+  float lat1;
+  float lon1;
+  float lat2;
+  float lon2;
+}
+
+@property float lat1;
+@property float lon1;
+@property float lat2;
+@property float lon2;
+
+- (id)init;
+- (id)initWithLat1:(float)newLat1
+              lon1:(float)newLon1
+              lat2:(float)newLat2
+              lon2:(float)newLon2;
+- (float)distance;
+- (float)toKilometers;
+- (float)toMeters;
+- (float)toMiles;
+- (float)toFeet;
+
+@end

Haversine.m

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+//
+//  haversine.m
+//
+//  Created by Carsten Nielsen.
+//
+
+#import "Haversine.h"
+
+float const HAVERSINE_RADS_PER_DEGREE = 0.0174532925199433;
+float const HAVERSINE_MI_RADIUS = 3956.0;
+float const HAVERSINE_KM_RADIUS = 6371.0;
+float const HAVERSINE_M_PER_KM = 1000.0;
+float const HAVERSINE_F_PER_MI = 5282.0;
+
+
+@implementation Haversine
+
+@synthesize lat1, lon1, lat2, lon2;
+
+- (id)init {
+  return [self initWithLat1:0.0 lon1:0.0 lat2:0.0 lon2:0.0];
+}
+
+- (id)initWithLat1:(float)newLat1
+              lon1:(float)newLon1
+              lat2:(float)newLat2
+              lon2:(float)newLon2 {
+  self = [super init]; 
+  if (self) {
+    self.lat1 = newLat1;
+    self.lon1 = newLon1;
+    self.lat2 = newLat2;
+    self.lon2 = newLon2;
+  }
+  return self; 
+}
+
+- (float)distance {
+  float lat1Rad = lat1 * HAVERSINE_RADS_PER_DEGREE;
+  float lat2Rad = lat2 * HAVERSINE_RADS_PER_DEGREE;
+  float dLonRad = ((lon2 - lon1) * HAVERSINE_RADS_PER_DEGREE);
+  float dLatRad = ((lat2 - lat1) * HAVERSINE_RADS_PER_DEGREE);
+  float a = pow(sin(dLatRad / 2), 2) + cos(lat1Rad) * cos(lat2Rad) * pow(sin(dLonRad / 2), 2);
+  return (2 * atan2(sqrt(a), sqrt(1 - a)));
+}
+
+- (float)toKilometers {
+  return [self distance] * HAVERSINE_KM_RADIUS;
+}
+
+- (float)toMeters {
+  return [self toKilometers] * HAVERSINE_M_PER_KM;
+}
+
+- (float)toMiles {
+  return [self distance] * HAVERSINE_MI_RADIUS; 
+}
+
+- (float)toFeet {
+  return [self toMiles] * HAVERSINE_F_PER_MI;
+}
+
+@end