package dk.daoas.fulddaekning;



public class GeoPointHelper {


	
	// Latitude (horizonal), longitude(vertical) so
	// 1 degree latitude is ~ 111320 meters, since the distance between the
	// horizonal lines is always the same
	// 1 degree longitude is ~111320 meters at equator but gets shorter as we
	// get closer to the poles.
	// so 1 degree longitude is 64.5 km at denmarks southern point
	// (gedser=54.55,11.95)
	// and is 59.4km at northern point (skagen = 57.75,10.65)

	public static double kmToLatitude(double km) {
		return km / 111.320;
	}

	public static double kmToLongitude(double km) {// denne er kun ca
		return km / 62.0;
	}
	
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

	/* ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: */
	/* :: This function converts decimal degrees to radians : */
	/* ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: */
	private static double deg2rad(double deg) {
		return (deg * Math.PI / 180.0);
	}

	/* ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: */
	/* :: This function converts radians to decimal degrees : */
	/* ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: */
	private static double rad2deg(double rad) {
		return (rad * 180 / Math.PI);
	}

	// http://www.geodatasource.com/developers/java
	private static double distanceHaversine(double lat1, double lon1,
			double lat2, double lon2) {
		double theta = lon1 - lon2;
		double dist = Math.sin(deg2rad(lat1)) * Math.sin(deg2rad(lat2))
				+ Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2))
				* Math.cos(deg2rad(theta));
		dist = Math.acos(dist);
		dist = rad2deg(dist);
		dist = dist * 60 * 1.1515;

		// indtil nu er dist i miles - så vi omregner lige til km
		dist = dist * 1.609344;
		return (dist);
	}

	public static double beregnAfstand(Adresse p1, Adresse p2) {
		if (p1.latitude == p2.latitude && p1.longitude == p2.longitude) {
			return 0.00; //Haversine går i baglås hvis p1 og p2 er samme position
		}
		
		
		return distanceHaversine(p1.latitude, p1.longitude, p2.latitude, p2.longitude);
	}
	
}