Beispiel #1
0
 /**
  * Returns the <a href="http://en.wikipedia.org/wiki/Rhumb_line">rhumb line</a> bearing from the
  * current location to the GeoLocation passed in.
  *
  * @param location destination location
  * @return the bearing in degrees
  */
 public double getRhumbLineBearing(GeoLocation location) {
   double dLon = Math.toRadians(location.getLongitude() - getLongitude());
   double dPhi =
       Math.log(
           Math.tan(Math.toRadians(location.getLatitude()) / 2 + Math.PI / 4)
               / Math.tan(Math.toRadians(getLatitude()) / 2 + Math.PI / 4));
   if (Math.abs(dLon) > Math.PI) dLon = dLon > 0 ? -(2 * Math.PI - dLon) : (2 * Math.PI + dLon);
   return Math.toDegrees(Math.atan2(dLon, dPhi));
 }
Beispiel #2
0
 /**
  * Returns the <a href="http://en.wikipedia.org/wiki/Rhumb_line">rhumb line</a> distance from the
  * current location to the GeoLocation passed in.
  *
  * @param location the destination location
  * @return the distance in Meters
  */
 public double getRhumbLineDistance(GeoLocation location) {
   double R = 6371; // earth's mean radius in km
   double dLat = Math.toRadians(location.getLatitude() - getLatitude());
   double dLon = Math.toRadians(Math.abs(location.getLongitude() - getLongitude()));
   double dPhi =
       Math.log(
           Math.tan(Math.toRadians(location.getLongitude()) / 2 + Math.PI / 4)
               / Math.tan(Math.toRadians(getLatitude()) / 2 + Math.PI / 4));
   double q = (Math.abs(dLat) > 1e-10) ? dLat / dPhi : Math.cos(Math.toRadians(getLatitude()));
   // if dLon over 180° take shorter rhumb across 180° meridian:
   if (dLon > Math.PI) dLon = 2 * Math.PI - dLon;
   double d = Math.sqrt(dLat * dLat + q * q * dLon * dLon);
   return d * R;
 }
Beispiel #3
0
  /**
   * Calculate <a href="http://en.wikipedia.org/wiki/Great-circle_distance">geodesic distance</a> in
   * Meters between this Object and a second Object passed to this method using <a
   * href="http://en.wikipedia.org/wiki/Thaddeus_Vincenty">Thaddeus Vincenty's</a> inverse formula
   * See T Vincenty, "<a href="http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf">Direct and Inverse
   * Solutions of Geodesics on the Ellipsoid with application of nested equations</a>", Survey
   * Review, vol XXII no 176, 1975
   *
   * @param location the destination location
   * @param formula This formula calculates initial bearing ({@link #INITIAL_BEARING}), final
   *     bearing ( {@link #FINAL_BEARING}) and distance ({@link #DISTANCE}).
   * @return geodesic distance in Meters
   */
  private double vincentyFormula(GeoLocation location, int formula) {
    double a = 6378137;
    double b = 6356752.3142;
    double f = 1 / 298.257223563; // WGS-84 ellipsiod
    double L = Math.toRadians(location.getLongitude() - getLongitude());
    double U1 = Math.atan((1 - f) * Math.tan(Math.toRadians(getLatitude())));
    double U2 = Math.atan((1 - f) * Math.tan(Math.toRadians(location.getLatitude())));
    double sinU1 = Math.sin(U1), cosU1 = Math.cos(U1);
    double sinU2 = Math.sin(U2), cosU2 = Math.cos(U2);

    double lambda = L;
    double lambdaP = 2 * Math.PI;
    double iterLimit = 20;
    double sinLambda = 0;
    double cosLambda = 0;
    double sinSigma = 0;
    double cosSigma = 0;
    double sigma = 0;
    double sinAlpha = 0;
    double cosSqAlpha = 0;
    double cos2SigmaM = 0;
    double C;
    while (Math.abs(lambda - lambdaP) > 1e-12 && --iterLimit > 0) {
      sinLambda = Math.sin(lambda);
      cosLambda = Math.cos(lambda);
      sinSigma =
          Math.sqrt(
              (cosU2 * sinLambda) * (cosU2 * sinLambda)
                  + (cosU1 * sinU2 - sinU1 * cosU2 * cosLambda)
                      * (cosU1 * sinU2 - sinU1 * cosU2 * cosLambda));
      if (sinSigma == 0) return 0; // co-incident points
      cosSigma = sinU1 * sinU2 + cosU1 * cosU2 * cosLambda;
      sigma = Math.atan2(sinSigma, cosSigma);
      sinAlpha = cosU1 * cosU2 * sinLambda / sinSigma;
      cosSqAlpha = 1 - sinAlpha * sinAlpha;
      cos2SigmaM = cosSigma - 2 * sinU1 * sinU2 / cosSqAlpha;
      if (Double.isNaN(cos2SigmaM)) cos2SigmaM = 0; // equatorial line: cosSqAlpha=0 (§6)
      C = f / 16 * cosSqAlpha * (4 + f * (4 - 3 * cosSqAlpha));
      lambdaP = lambda;
      lambda =
          L
              + (1 - C)
                  * f
                  * sinAlpha
                  * (sigma
                      + C
                          * sinSigma
                          * (cos2SigmaM + C * cosSigma * (-1 + 2 * cos2SigmaM * cos2SigmaM)));
    }
    if (iterLimit == 0) return Double.NaN; // formula failed to converge

    double uSq = cosSqAlpha * (a * a - b * b) / (b * b);
    double A = 1 + uSq / 16384 * (4096 + uSq * (-768 + uSq * (320 - 175 * uSq)));
    double B = uSq / 1024 * (256 + uSq * (-128 + uSq * (74 - 47 * uSq)));
    double deltaSigma =
        B
            * sinSigma
            * (cos2SigmaM
                + B
                    / 4
                    * (cosSigma * (-1 + 2 * cos2SigmaM * cos2SigmaM)
                        - B
                            / 6
                            * cos2SigmaM
                            * (-3 + 4 * sinSigma * sinSigma)
                            * (-3 + 4 * cos2SigmaM * cos2SigmaM)));
    double distance = b * A * (sigma - deltaSigma);

    // initial bearing
    double fwdAz =
        Math.toDegrees(Math.atan2(cosU2 * sinLambda, cosU1 * sinU2 - sinU1 * cosU2 * cosLambda));
    // final bearing
    double revAz =
        Math.toDegrees(Math.atan2(cosU1 * sinLambda, -sinU1 * cosU2 + cosU1 * sinU2 * cosLambda));
    if (formula == DISTANCE) {
      return distance;
    } else if (formula == INITIAL_BEARING) {
      return fwdAz;
    } else if (formula == FINAL_BEARING) {
      return revAz;
    } else { // should never happpen
      return Double.NaN;
    }
  }