code: public static double crossTrackDistanceDeg(double lat1, double lon1, double lat2, double lon2, double latQ, double lonQ) {
      return crossTrackDistanceRad(deg2rad(lat1), deg2rad(lon1), deg2rad(lat2), deg2rad(lon2), deg2rad(latQ), deg2rad(lonQ));
    }
docs: Compute the cross-track distance.
  <p>
  XTD = asin(sin(dist_1Q)*sin(crs_1Q-crs_12))
  
  @param lat1 Latitude of starting point.
  @param lon1 Longitude of starting point.
  @param lat2 Latitude of destination point.
  @param lon2 Longitude of destination point.
  @param latQ Latitude of query point.
  @param lonQ Longitude of query point.
  @return Cross-track distance in km. May be negative - this gives the side.