LongitudeLatitudeUtil

import java.text.DecimalFormat;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Parses longitude or latitude to double
 */
public class LongitudeLatitudeUtil {

  private static String EXPRESSION = "^(?<deg>[-+0-9]+)[^0-9]+(?<min>[0-9]+)[^0-9]+(?<sec>[0-9.,]+)[^0-9.,ENSW]+(?<pos>[ENSW]*)$";

	/**
	 * Parses the latitude and longitude to double
	 * 
	 * @param value
	 * @return
	 */
	public static double ParseLatLonValue(String value) {
		double result = Double.NaN;
		/**
		 * Remove the double quote from both sides if present
		 */
		if (value.startsWith("\"") && value.endsWith("\"")) {
			value = value.substring(1, value.length() - 2).replace("\"\"", "\"");
		}
		Pattern pattern = Pattern.compile(EXPRESSION);
		Matcher matcher = pattern.matcher(value);
		double deg = Double.NaN;
		double min = Double.NaN;
		double sec = Double.NaN;
		char pos = '\0';
		if (matcher.matches()) {
			deg = Double.parseDouble(matcher.group("deg"));
			min = Double.parseDouble(matcher.group("min"));
			sec = Double.parseDouble(matcher.group("sec"));
			pos = matcher.group("pos").charAt(0);
			result = parseLatLonValue(deg, min, sec, pos);
		}
		return result;
	}

	/**
	 * @param deg
	 * @param min
	 * @param sec
	 * @param pos
	 * @return
	 */
	public static double parseLatLonValue(double deg, double min, double sec, char pos) {
		double result = deg + (min / 60) + (sec / 3600);
		// North and East are positives and so adjustment for S W
		result = ((pos == 'S') || (pos == 'W')) ? -result : result;
		return result;
	}

	/**
	 * @param value
	 * @return
	 */
	private static String parseLatLonValue(double value) {
		double absoluteValue = Math.abs(value);
		int deg = (int) Math.floor(absoluteValue);
		absoluteValue = (absoluteValue - deg) * 60;
		int min = (int) Math.floor(absoluteValue);
		double seconds = (absoluteValue - min) * 60;
		DecimalFormat twoDForm = new DecimalFormat("#.##");
		seconds = Double.valueOf(twoDForm.format(seconds));
		return deg + "°" + min + "'" + seconds;
	}

	/**
	 * @param value
	 * @return
	 */
	private static String parseSpaceLatLonValue(double value) {
		double absoluteValue = Math.abs(value);
		int deg = (int) Math.floor(absoluteValue);
		absoluteValue = (absoluteValue - deg) * 60;
		int min = (int) Math.floor(absoluteValue);
		double seconds = (absoluteValue - min) * 60;
		DecimalFormat twoDForm = new DecimalFormat("#.##");
		seconds = Double.valueOf(twoDForm.format(seconds));
		return deg + " " + min + "' " + seconds + "''";
	}

	/**
	 * @param value
	 * @return
	 */
	public static String parseSpaceLatitude(double value) {
		String direction = value < 0 ? "S" : "N";
		String strValue = parseSpaceLatLonValue(value);
		return strValue + " " + direction;
	}

	/**
	 * @param value
	 * @return
	 */
	public static String parseSpaceLongitude(double value) {
		String direction = value < 0 ? "W" : "E";
		String strValue = parseSpaceLatLonValue(value);
		return strValue + " " + direction;
	}

	/**
	 * @param value
	 * @return
	 */
	public static String parseLatitude(double value) {
		String direction = value < 0 ? "S" : "N";
		String strValue = parseLatLonValue(value);
		return strValue + "\"" + direction;
	}

	/**
	 * @param value
	 * @return
	 */
	public static String parseLongitude(double value) {
		String direction = value < 0 ? "W" : "E";
		String strValue = parseLatLonValue(value);
		return strValue + "\"" + direction;
	}

	/**
	 * @param lat1
	 * @param lon1
	 * @param lat2
	 * @param lon2
	 * @param unit
	 *            M = Miles K = Kilometer N = NauticalMiles
	 * @return
	 */
	public static double distance(double lat1, double lon1, double lat2, double lon2, char unit) {
		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;
		if (unit == 'K') {
			dist = dist * 1.609344;
		} else if (unit == 'N') {
			dist = dist * 0.8684;
		}
		if (!Double.isNaN(dist) && !Double.isInfinite(dist)) {
			DecimalFormat twoDForm = new DecimalFormat("#.##");
			dist = Double.valueOf(twoDForm.format(dist));
		}
		return (dist);
	}

	private static double deg2rad(double deg) {
		return (deg * Math.PI / 180.0);
	}

	private static double rad2deg(double rad) {
		return (rad * 180.0 / Math.PI);
	}

	/**
	 * @param lat1
	 * @param lon1
	 * @param lat2
	 * @param lon2
	 * @return
	 */
	public static double[] midPoint(double lat1, double lon1, double lat2, double lon2) {
		double dLon = Math.toRadians(lon2 - lon1);
		lat1 = Math.toRadians(lat1);
		lat2 = Math.toRadians(lat2);
		lon1 = Math.toRadians(lon1);

		double Bx = Math.cos(lat2) * Math.cos(dLon);
		double By = Math.cos(lat2) * Math.sin(dLon);
		double latitudeMidPoint = Math.atan2(Math.sin(lat1) + Math.sin(lat2), Math.sqrt((Math.cos(lat1) + Bx) * (Math.cos(lat1) + Bx) + By * By));
		double longitudeMidPoint = lon1 + Math.atan2(By, Math.cos(lat1) + Bx);
		return new double[] { Math.toDegrees(longitudeMidPoint), Math.toDegrees(latitudeMidPoint) };
	}

	/**
	 * @param lat1
	 * @param lon1
	 * @param lat2
	 * @param lon2
	 * @return
	 */
	public static double[] midPoint(String lat1, String lon1, String lat2, String lon2) {
		double lat11 = ParseLatLonValue(lat1);
		double lon11 = ParseLatLonValue(lon1);
		//
		double lat22 = ParseLatLonValue(lat2);
		double lon22 = ParseLatLonValue(lon2);
		return midPoint(lat11, lon11, lat22, lon22);
	}

	/**
	 * NOT TESTED YET 
	 * @param lat1
	 * @param lon1
	 * @param lat2
	 * @param lon2
	 * @return
	 */
	public static double bearing(double lat1, double lon1, double lat2, double lon2) {
		//
		double longitude1 = lon1;
		double longitude2 = lon2;
		double latitude1 = Math.toRadians(lat1);
		double latitude2 = Math.toRadians(lat2);
		double longDiff = Math.toRadians(longitude2 - longitude1);
		double y = Math.sin(longDiff) * Math.cos(latitude2);
		double x = Math.cos(latitude1) * Math.sin(latitude2) - Math.sin(latitude1) * Math.cos(latitude2) * Math.cos(longDiff);
		return (Math.toDegrees(Math.atan2(y, x)) + 360) % 360;
	}

	/**
	 * @param longitude1
	 * @param longitude2
	 * @return if first Point is on west side of 2nd point
	 */
	public static boolean isWest(double longitude1, double longitude2) {
		return longitude1 < longitude2;
	}

}